Sculptie Stitch Type

 Mesh, MV-SL-Tutorials, Tutorials  10 Responses »
Apr 102010
 

In this tutorial you will learn some unique ways to use stitch types with your sculpties, such as making sculpt ends that are a line instead of a single pinch point.

What are Stitch Types?

Stitch types determine how Second Life interprets the edges of a sculpt map in order to render your sculpted prim.

Plane Stitching

Plane stitching is like a square piece of cloth, or like a sheet of paper. When you select this stitch type, Second Life does not assume that any of the edges of your sculptie will touch each other.

You can manually put the edges together yourself, but Second Life will not try to “fill in” between the seams. This can be useful for things like landscape sculpts and table cloths.

Note that in SL, only one side of a plane mesh is visible.  The other side will be completely transparent.  For example, if you make a table cloth with a plane sculptie, the underside will be invisible.

Cylinder Stitching

Cylinder stitching is like wrapping that cloth around and sewing two sides together, to make it into a tube.  We can still bend and stretch the tube however we want, but now two sides MUST remain together.

When you use this stitch type, if the left and right edges of your sculptie don’t touch, Second Life will automatically fill that information in so that they do. However, the top and bottom may remain open.  You can, of course, close the top and bottom manually (which is something that I do OFTEN!  Keep reading.)

The inside of the cylinder will be invisible, like the underside of the plane.

Torus Stitching

Imagine that we stretch the cylinder so that it’s really tall and skinny, then bend it around into the shape of a donut so that the top and bottom meet.  This is like “Torus” stitching in Second Life, where Second Life assumes that the left/right, and top/bottom sides will be stitched together.

If you use this stitch type and the edges of your sculpt don’t meet, once again, Second Life will attempt to fill in between the edges anyway.

Sphere (default) Stitching

Lastly, instead of making a torus, imagine taking the cylinder and pinching the top and bottom into a single point.  This is Sphere stitching, and is the default stitching in Second Life.  It assumes that the top and bottom of your sculpt map will come to a single point.

If you use this stitch type, even if the top and bottom of your mesh are something other than a point, Second Life will FORCE them into a point anyway.  This is the main reason why sphere stitching is often not the best stitch type to use.

Because all of the ends on Sphere and Torus stitching are closed up, you will never see the invisible side of these sculpted prims.

Using Stitch Types

You might be looking at this information and wondering what the point is. After all, many people seem to get along fine with just the default sphere stitching.  Maybe you can see a use for some of them, like making loop-type objects with torus stitching, or landscapes with plane stitching, but are there that many uses for these other stitch types?

But really, the value in these other stitch types isn’t in their obvious uses.  It’s in the ability to take advantage of these open edges to do things that you might not at first think of.  Take, for example, this collar from a tuxedo set that I bought:

The tuxedo that this came with was in all other respects fantastic.  But you can see how the front ends of the collar are all wrinkled up, like crumpled paper.  Now look at a shirt collar that I made for one of my own outfits:

The ends of my collar aren’t perfect, but they don’t have the crumpled look.  The crumpled ends are a result of the stitch type used to create it.  The first collar uses the default sphere stitching.  My collar uses cylinder stitching.  Let me show you.

To make a collar in Blender, I often start out with a cylinder that’s been modified into a sort of flat, long shape, like the image on the left.

In order to make a shirt collar from this, we need to curve it in two directions.  First, to make the arch of the collar, then to curve it around the neck.  These two curves make collars a particularly interesting challenge for a sculptor.

So lets think about stitch types.  Default stitching is Sphere stitching, which forces the ends to pinched to a single point, so lets do that to the ends of the mesh.

Now lets create the arch of the collar.  Switch to the side view, looking at the new stitched ends.  Select all of your vertices (tap A) and place the 3D Cursor (that circle thing with the cross-hairs) somewhere below the mesh (place it by left-clicking inside the 3D window.)

Now press Shift-W to Warp the mesh around the 3D Cursor.

You can already see a problem.  Because all of the end vertices come to a single point, instead of a nice arch the ends look something like the image above.

We could try using a few edge loops to push around the edges and force the ends into arch, like the image on the left.  That’s what the creator of that tuxedo set did and that’s where the crumpled edges on that first collar came from, so it ends up looking kinda ugly, not to mention the wasted edge loops.

So what can cylinder stitching do for us?  We may not want the ends of the collars to pinch, but we also don’t want them open, showing off the invisible inside.

I’ve already told you that we can force a cylinder’s ends closed.  For example, we could manually pinch them off, like sphere stitching, but that doesn’t do us much good.  But what if we close off a cylinder in a way that we COULDN’T do with sphere stitching?

Here, instead of pinching the ends off to a point, we only pinch them in one direction, creating a seam – a line of vertices.  This still effectively closes off the ends, but in a much different way than what we could get with sphere stitching.  Look what happens when we curve the mesh.

Now we have a much nicer, clean edge to work with.  If we bake this sculptie and import it into Second Life, if we select Cylinder stitching on the new sculptie, we will also get this line seam.

Aside from collars, this sort of  straight-line edge can also help with texturing.  Look at these two beveled cubes.  The one on the left has default sphere-type stitching.  The one on the right was built to use cylinder stitching.  This makes for a much nicer texture layout.

If you aren’t convinced yet at the power of different stitch types, let me show you a few examples.  I won’t tell you exactly how they’re done or why I used the stitch type that I did.  Instead, look at them and try to figure it out for yourself. As always, I’m not an all-knowing expert.  You may see a better way to do things than what I’ve done, but this may give you some ideas anyway.

Stitching Examples:

Think outside the box.  There are tons of ways to use stitch type to your advantage, to create shapes that you normally couldn’t create, or to clean up a mesh that has nasty ends or texturing issues.  If you do something particularly neat, you might consider showing it off in the new forums.

Oblong Tessellation

 Mesh, MV-SL-Tutorials, Tutorials  No Responses »
Mar 222010
 

In this tutorial you will learn how to use Oblong Tessellation to get better results with long, skinny sculpts like pipes and chair frames. I use Oblong Tessellation for many other things too, so it’s a useful tool to add to your own knowledge.

The Long and Short of It

A lot of you probably looked at the term “Oblong Tessellation” and went cross-eyed.  Don’t worry. I did too.

But after looking into it, I figured out that it’s just a freakishly complex name for a pretty simple concept.  All we’re doing is rearranging the sculptie’s vertices so that instead of a perfect square 32×32 grid, we have a rectangular grid at 16×64, or 8×128.

Above, you can see the difference between a normal sculpt map and one that uses oblong tessellation.

Why is this useful? Let me break it down for you.

The Pipe Problem

Lets say you want to make a sculptie pipe to import into Second Life. You want this pipe to be long, skinny, and as windy as possible. You decide to use three edge loops per bend to keep the pipe looking nice.

Using the default 32×32 mesh, you come up with something like the image on the left. You wind up with nine or ten bends, which is okay, but not as bendy as you’d like. (Note that if you had accounted for any amount of LoD, you’d have even less bends then that!)
Now take a look at the cross section of this pipe and you’ll begin to see the problem.

There are 32 points on every edge loop, which is a problem in more than one way.

First of all, you don’t need 32 vertices to make something that skinny look round. These are wasted vertices.

Second, sculpties start doing weird things when you have a lot of vertices in a small area. The more points you have in a small area, the more chance you have for jagged edges when you import that sculpt into Second Life.

So. What do we do? We make an oblong sculptie! This is pretty easy to do. When you bring up the dialogue to create a sculptie, by default it shows 8 x 8 faces with 2 levels of multires. Change this to 4 x 16. When you enter the number for Y, initially, it will turn black and the Build button will be greyed out. Usually this just means the dialog wants you to press Enter so it can recalculate your sculpt mesh.

There are a lot of different sizes that you can make your sculptie. For a complete list, look here. Sizes are listed as (face)x(face)x(multirez). However it doesn’t seem like Second Life can handle all of these sizes correctly. The only sizes that I’ve gotten to work (at least with with anything practical) are 8×8(x2) and 4×16(x2), and 4×64(x1).

Look at the cross section of this new sculptie.

Now each edgeloop has half the number of vertices, which is still plenty to make it look round. We aren’t wasting nearly as many points, and we won’t have so many problems with edges becoming choppy.

What’s more is, those points we took from the diameter of our edge loops now go into making the length of the pipe. We can add even more bends. (Or we can work with multires so our pipe doesn’t loose it’s shape at a distance.)

Look at the difference between our original pipe and the oblong pipe. We have a lot more to work with. This doesn’t just apply to pipes. It’ll work for anything that has a long, skinny shape, like the frame of a dining chair, or scaffolding for a building, or a streetlamp, or a pencil twisted in the shape of a heart!

Baking an Oblong Sculptie

Domino’s new primstar scripts automatically assigns your mesh an image sized based on the faces and and subdivision levels that you started with.

So if you started with a mesh with 8 x 8 faces and 2 subdivision levels, it will assign a 64 x 64 image.

If you start with a 4 x 16 mesh and 2 levels of subdivision, it will assign a 32 x 128 image.

In previous versions of my starter tutorials, I instructed people to start without subdivision levels (no multires) because I felt it was easier ( and I STILL feel it’s easier) to start defining a mesh with less vertices.

However, if you start with an 8×8 mesh and no subdivision, your mesh will be assigned a 16×16 image, which isn’t what you want. So now it’s better to start with the 2 levels of subdivision and then manually delete the higher levels if you wish to start with a simpler mesh.

Tips, Tricks, and Notes

Oblong Tesselation is still rather new and while I use it all the time now, I can’t, for the moment, think of any tips specifically related to it.

But as a note, there is some functionality of oblong tessellation that’s still being developed. Particularly the ability to use LESS vertices than the current 1024, which would be useful for certain simple geometric shapes.

Multi-Sculptie Builds

 Mesh, MV-SL-Tutorials, Tutorials  42 Responses »
Mar 212010
 

In this tutorial you’ll learn how to make objects with more than one sculptie in Blender, and import all of it into Second Life, plus how to make duplicate sculpties in your blender file.

E Pluribus Unum

Sometimes it’s necessary to build an object with more than one sculptie. A knee-high boot, for instance, may need to be attached to more than one bone on the SL skeleton, or an object may have clearly different pieces like a belt and a buckle or a sword with a sheath, or a shape may simply be too complex to do easily with one sculptie.

You can model all of the sculpties you need in the same .blend file to be sure that the two sculpties fit together, and to do useful texture tricks, like having the sculpties cast shadows on each other. (See this tutorial)

Primstar Scripts

Domino’s new Primstar scripts actually include the ability to export multiple sculpties with a script that will let you recreate a multi sculpt object in Second Life.

Once you have things finished the way you want in Blender, bake the sculpt maps for all the sculpties you want to export. Next, select all the sculpt meshes in Object Mode, making sure the root prim is highlighted in bright pink.

Press Ctrl-P and select “Make Parent”. Double check that the other meshes are parented by selecting just the root object and moving it around. If the other objects follow, you’ve got it.

With that root object selected, go to the top menu and select File > Export > Second Life LSL (to dir). Browse to a folder (preferably an empty one) and hit ‘export’. This should save all of your sculpt maps and ONE plain text file with the extension .lsl. Open this lsl file with a program like Notepad, select all the text and copy it.

In world, rez a plain cube on the floor. Upload all of the sculpt maps and add them to the contents of your box. Next, create a new script inside the box, then double-click the new script to edit it. Delete the default script and replace it with the text you copied from the .lsl file.

Hit Save, and after a few seconds, the script will ask you to create a prim, name it “Primstar” and put it into the box. Do that. Then the script will ask you for linking permissions. Once you give the permissions, the script will start recreating your object in world, ending by linking everything together.


Duplicating a Sculptie

If you want to make a single sculptie that will be used on multiple parts of your build, go into Object mode and press Alt-D. And move the new object to where you want it.

This will create a new object, but the mesh for both will remain identical. If you edit the mesh in Edit Mode, both objects with change. If you scale/rotate/move the object in Object Mode, it will only effect the one object.

If the shape you need for a new sculpt mesh is similar to a mesh you already have, but not identical, go to Object Mode and press SHIFT-D instead. This will create a copy, but both the object and the mesh will be separate, so you can edit the new one without effecting the old one.

Currently, the Primstar scripts don’t seem to understand exporting objects with duplicate sculpts. I tried exporting a skull that used a lot of duplicate sculpts for the teeth, and that broke the lsl script pretty bad. xD So keep that in mind if you’re planning on using it.

Adding a Mesh from an Older File

If you have a sculptie from a previous file that you’d like to add/edit in your current one, you can ‘append’ the object.

You may want to save your current file now, in case of error. Now we’ll be using a function in Blender that lets you browse inside another .blend file and select a part to add to your current file. Go to File > Append or Link.

From here, you may actually start inside your current .blend file, which is useless because Blender doesn’t let you append anything from inside your current file. (Can someone explain to me why Blender does this?) Hit “..” until you see the contents of your save directory, then find the .blend file that contains the mesh you want to append and click it, then click “Object”. From here you’ll see a list of the objects in that file. Hopefully you’ve renamed your sculptie objects so that you can easily identify them. Select the one you want, and click “Load Library.”

If you haven’t been doing it already, it’s good practice to rename your objects in Blender

This makes browsing with the Append feature easier, and also lets Primstar name your sculpt maps or you before you export them to your hard drive.

Make One Sculptie Look Like Two… or Three… or Four

 Mesh, MV-SL-Tutorials, Tutorials  8 Responses »
Mar 212010
 

In this tutorial, you’ll learn how to make a single sculptie look like more than one object.

Making the Cut

If you look at the image here, the cushions on this chair are both the same sculpted prim. They are connected by a tiny, invisible line of points. I’ll be showing you how to do just that. Before you read this tutorial, it’s recommended that you go through the Precision Sculptie tutorial.

The method was developed by Aminom Marvin.

The Long and Short of It
(Or… just short)

Okay. You want to know how to do this? I warn you. You will gawk at the simplicity.

Select one loop of vertices and scale it to 0. (You can scale to zero easily by tapping S, then the number 0.)

Then select the loop just above or below and scale it to 0 as well. Be sure you deselect the previous loop. (Did you know that you can select a loop in Blender by holding ALT and right-clicking on one of the edges in the loop?)

Congratulations! You just made a fractional sculptie! If you bake this and import it into Second Life, it will look like two separate objects. Maybe

Maybe? Yes. The pole may still show up. It will be thin, but it will be there, until you snap the vertices to the Precision Grid!

The Precision WHAT?

If you have no idea what I’m talking about, you need to read through the Precision Sculptie tutorial. If you have read it, you might want to run through it again real quick, cause I’m not going to repeat much here.

Just remember that you need to set the grid to .01, scale the object to 2.55 x 2.55 x 2.55, line it up to the grid, then snap your vertices to the grid. After you’ve done this, you can bake your sculpt map and import it into Second Life and you should have completely invisible poles.

Tricks, Tips, and Notes

For simplicity’s sake I’m going to be referring to the separate sections of a fractioned sculptie as “pieces.” So in the first example in this tutorial, the sculptie would be separated into the top piece and the bottom piece.

Trick: Half Poles

If the one-point poles are taking away too many points for you, sometimes you can get away with using what I call ‘half poles.’ This only works if an end of one of the pieces will end up inside of another piece – hidden. Like…. THIS:


A brief summary of what’s going on here. I only pinched off a single loop, instead of two, then cap off the piece that will have the visible end. Then I resized the other piece so that the end would fit inside the capped piece (reduces clipping and other uglification problems). Then I rotated the smaller piece and repositioned it so that the connected end is now inside the larger piece. All the crap in between the two ends is inside the larger piece. No one’s going to see it, unless they’re trying to figure out how you made your awesome sculptie.

Tip: Don’t do it when you don’t need to.

I’ve seen a few people use Fractional Prim Modeling in cases when it’s really not necessary. Like… if you’re making a 1-prim sculptie hamburger, you probably don’t need to completely separate the patty from the buns. You’d just end up wasting vertices.

Often times you can get better results by using other methods to visually divide a sculptie. Be smart about it.

Creating and Using Shadow Maps

 MV-SL-Tutorials, Texturing, Tutorials  22 Responses »
Mar 202010
 

In this tutorial you will learn how to create a shadow map on your sculpties that you can use to create high-quality textures for your sculpts.

Texturing with Shadow Maps

For some sculpties, slapping on a tileable texture from your inventory might work well enough.

Often, however, it looks better if you create a texture specifically for your sculptie. Sometimes this is even necessary to get the look that you want. The trouble is, how do you make a texture that fits your sculptie exactly?

I’ve often seen people use a colored and numbered grid to map out the general location of certain parts of a sculptie, then match it to the same grid in 2D format. While this method has its place, it can get pretty tedious.

There are features in Blender that will help us make textures for our sculpties relatively quickly. In this tutorial we’re going to focus on baking ambient shadows, which is probably the fastest and easiest to understand method available in Blender.

In this tutorial, I ask that you have your screen split in half and one half switched to the UV/Image Editor.

Ambient Occlusion

Before we begin, I want to change the draw type in the 3D View to Textured. Find the small menu to the right of the Mode menu (marked in red – click the image to enlarge) and switch the draw type to Textured. If your sculptie is currently assigned a UV texture (such as a sculpt map), you’ll see that texture placed onto your mesh in the 3D View.

If you’ve ever worked with other Blender sculptie templates, you may already know how to bake textures onto an image. However there are other types of images we can bake. The type we’re going to bake now is Ambient Occlusion – or global shadows.

First we want to assign our mesh to a new texture. If you have multires on your mesh, you need to switch to Level 1 or Apply Multires before you change textures. Then go into edit mode and select All, by tapping A until all the vertices are yellow and the faces pink. Then in the UV/Image Editor, go to the menu Image > New. Make a new image that’s 256 x 256 or 512 x 512. Hit OK. (If you switched to Multires level 1, you can now switch back to level 3.)

Now go to the Scene > Render Buttons (marked in green – click the image to enlarge) and then find the Bake tab (blue) and change the bake type to “Ambient Occlusion” (yellow) and hit Bake. Wait a few moments for Blender to bake shadows onto your image. Save the image as something meaningful.

Usually this shadow map gives you enough ‘landmarks’ on the texture to be able to paint a texture that exactly fits your sculptie. Just use your favorite image editing software.

If you get black lines running through your shadow map, like the image above, this is something that happens in Blender sometimes, especially if there are faces on your sculpt that are twisted. Either paint these out, or blur them, or find some other means to get rid of them in your image editing software.

Previewing Your Texture

Testing your texture before uploading is incredibly easy. Simply save your new texture right over the file you saved from Blender. Then in Blender, reload the texture file by selecting Image > Reload in the UV/Image Editor.

Your new texture will now be wrapped around your mesh.  If something’s wrong, but you’re not sure where it is on the image, you can select the faces on your mesh and it will highlight them in the UV/Image Editor.

Another Texture

Maybe you’d rather keep the original shadow map or maybe you have multiple texture that you want to preview, like if you’re doing multiple recolors.  You save these textures separately and then open them in Blender to preview on your mesh.  Go to Image > Open. Find the texture you want and hit “Open Image.”

Then in Edit Mode swith to Multires level 1, select all your vertices, and find the drop-down menu next to the UVs Menu (marked in yellow). Click the small button with the arrows and select your new image. From this menu, you can also switch back to your old image, or to any image currently opened in Blender.

Multi-Sculpt Bake

If you have more than one sculpt mesh in a single .blend file (see how here) then each mesh may effect the shadow baking of the others.

If you look at the image to the left (click to enlarge) you can see how the smaller mesh has created a dark shadow on the larger one.

Sometimes this is desirable, such as when you want a drop-shadow look on your group of sculpts, but if you’d rather they affect each other less or not at all, move the meshes away from each other before baking.

Note that this behavior can be useful if you need additional landmarks on your shadow map. For instance, if you want to place a logo or other decoration at a specific location on the mesh, you can add a new object to your file and place it at the desired location so ambient occlusion will bake a shadow on that spot.

Resolution Tricks

 Mesh, MV-SL-Tutorials, Tutorials  3 Responses »
Mar 202010
 

In this tutorial, you will learn some tricks to make your sculpties looks better at a distance, including the “shrinkage” trick.

LOD Can Kill

As you already know, sculpted prims switch between three resolutions depending on your camera’s distance from them in Second Life.

Sometimes the difference in resolution makes such minor differences in the sculptie that you can simply ignore it. However, sometimes the lower LOD levels end up looking bizarre, or you may simply want the sculptie to retain its resolution better.

The sculpties in the image above were all the same mesh in Blender, but the sculpt map image was changed to effect how the the resolution held up at different distances. The screenshot was taken with Object Detail in SL’s Preferences turned almost all the way down.

Remember Multires

Before I get into more technical tips and tricks, I want to remind you about the multires feature in Blender. I had you learn about that for a better reason than just to annoy you. Multires corresponds with Second Life’s LOD (Level of Detail) rendering.

If you start off modeling at the 8×8 resolution (level 1) then your sculptie will have a better chance of retaining it’s basic shape. At the 16x 16 resolution, you should try to include as much detail as you can. The 32 x 32 resolution should only add the most nit-picky details.

If you don’t remember anything about multires, go back to the multires tutorial and read up.

Texture Tricks

Often you can make the decreases in resolution less noticeable by using a high-quality texture on your sculpties. Baking on shadows, for instance, helps to visually define a form, which will make your object appear to be higher resolution than if you were relying on Second Life’s realtime shadow rendering.

To learn more about texturing sculpts in Blender, read this other tutorial.

Shrinkage

There is a more technical trick that will actually help keep your sculpt’s shape at greater distances.You can shrink them.

I don’t mean in SL. In Second Life, you’ll actually be making them bigger.

An Explanation

You see… the distance at which your sculpt loses resolution is relative to how large the sculpt is. The larger the sculpt, the farther away your camera can get before it loses resolution.

So, what we want to do is make the sculpt larger, but make it appear to be the same size.

Yeah, I know. Weird. But it can be done. You’ve probably seen sculpts that do something like it. Several of the freebie sculpts floating around don’t quite fit inside the bounding box when you scale them. Have you noticed? You can stretch and stretch these sculpts, but they they never seem like they stretch far enough! Well we’re going to do this on purpose.

Using Primstar

The new Primstar scripts allow you to shrink your sculptie when you bake the sculpt map.  When you bring up the Bake Sculpt Meshes dialog, you’ll see a box on the right marked “Range.”  The default values for each color value (or axis) are 0 to 255.

What you want to do is increase the values on the left and decrease the values on the right by the same amount.  I chose to increase the left values by 55 and decrease the right values by 55, because those numbers are easy to figure out.  (I’m lazy.)  The larger the difference between the original values and the new ones, the more your sculptie will shrink.

Image Editor Method

You can also do the same thing with some sort of image editor like Photoshop and decrease the color contrast. Some experience in Photoshop is recommended, because I’m going to describe how to do things in Photoshop, since I have practically no experience in any other image editing software.

Open your sculpt map in your image editing application. In Photoshop, the next step is to go to Image > Adjustments > Levels. Ignore Input Levels. You want to change Output Levels, and it needs to be changed by the same amount on both sides. The default values are 0 and 255. Once again, I usually change mine to 55 and 200 since those are easy numbers to figure out. And still. the greater the difference in the new values from the default, the more your sculpt will shrink. Once you’ve decided on your values hit ‘OK.’ Your sculpt map will look slightly greyed.

In some programs, you can use Brightness/Contrast and decrease the contrast, but this is less precise, and it doesn’t seem to do the same thing in Photoshop at all.

Upload your sculpt map and apply it to a sculpted prim. You’ll see it shrink. If you have the original sculpt uploaded, try placing the two next to each other, and stretching your shrunken sculpt so it looks the same size as the original. Then zoom out and watch how their resolution changes.

A Word of Warning

Although this is a neat trick, you can decrease the contrast on the sculpt map too much.

First of all, if your sculpt is not made phantom, the collision box will be as large as the bounding box, not the shrunken sculpt, but also, your sculpt can become deformed.

The image on above shows the same set of sculpts as the first image on this page, only with the Object detail in SL’s Preferences turned to Mid. Notice that the first two sculpts look identical. The third is slightly more choppy looking, and the fourth, obviously, is rather deformed. Below is what the sculpt maps look like:

The less contrast there is, the more values start to run into each other and the more choppy your sculpt will be. If you’ve done a good job with multires and texturing, there usually isn’t any reason to even get as shrunken as the third sculpt. Remember to use this trick wisely. Only when you absolutely need it, and only to the degree it’s needed.

Create Precise Sculpted Prims

 Mesh, MV-SL-Tutorials, Tutorials  10 Responses »
Mar 182010
 

In this tutorial, you’ll learn about the sculptie grid, how it effects your sculpts, and how you can place vertices of your sculpt mesh with precision.

For Your OCD

Usually, when you’re creating simple and organic shapes, using basic sculpting techniques works just fine.

However, if you want to make complex and highly precise sculpts, you may run into some problems with things like getting shapes perfectly symmetrical, or getting a shape to curve without getting jagged edges.

But you can get very accurate and smooth sculpted prims with the tools available in Blender, some advanced knowledge, and a little bit of patience.

Precision sculpting techniques can be used for creating:

Smooth, professional-looking archways
Complex, geometric shapes, like gears
A single sculptie that looks like multiple objects (see this tutorial)
Any other shape that needs to be highly accurate.

An understanding of the principles behind precision sculpting can also help you create cleaner meshes and avoid problems that might otherwise make your sculpties turn out looked jagged or distorted.

The Theory

You already know that a sculptie’s shape is defined by an image’s RGB values.

Consider this:

How many values are available in an RGB image. The total number is quite large, but for each individual channel, the answer is 256. Values range from 0 to 255.

So. Translate this to your sculptie. How many locations are available for the points of your sculpt map. It’s the same number as the available RGB values. There are 256 available location-values for each axis of your sculpt.

Think of it as a 3-Dimensional grid. 256 x 256 x 256. Then think of a ‘snap to grid’ function. If the points of your sculpt don’t fall on one of these grid points, when you bake your sculpt map, the points will be put at the NEAREST possible point. For most organic sculpties, this is fine, but if you need a precise sculpt, often this will put points far enough off the mark to make the sculpt look… bad.

Note: You decrease the number of available locations when you decrease the contrast of your sculpt to \’shrink\’ it, as this eliminates a good number of the RGB values that get used.

The Practice

So what we are going to do is actually set up this grid in Blender. Then, when we have the sculpt finished we can snap all the vertices to the grid, so that every vertex will be placed exactly how it will be when imported into Second Life.

For this part of the tutorial, open up a .blend file with a sculpt mesh that you would like more precision on. For the purposes of this tutorial, try to use a sculpt that is relatively simple, and has some sort of curve to it. Something like an archway or the hood of a VW Beetle would be good. I’ll be using the beveled archway shown above.Go to the menu below your 3D View window and navigate to View > View Properties. In the dialog that pops up, change the Grid Spacing to 0.01 and the Divisions to 1.

Make sure that you’re in Object Mode and select your sculpt mesh object. Then go to the menu below your 3D View window and navigate to Object > Transform Properties. Alternatively, you can just tap N.Change the dimensions of your object to 2.55 x 2.55 x 2.55. This will probably make your mesh look distorted, but what we did here is make it so that each .01 grid space represents a value on each 0-255 axis. At this point, my beveled arch looks like this:

Lastly, you want to place a corner of your mesh on the grid. Find a point on your mesh that makes a good “outer corner” of your mesh, such as one of the bottom ends of my arch. Zoom in so you can see the grid, then line up the corner with one of the grid points ( as shown here).

Now, if I was to snap the vertices to the grid right now, (Mesh > Snap > Selection to Grid) the results would look something like the mesh on the right:

You can see how the lines of vertices become rough. If I had exported a sculpt map from the mesh on the left, this ‘roughing up’ is exactly what would have happened. So what do we do? We perform an exercise in patience. We place our vertices on the grid BY HAND!

Don’t worry. You don’t need to place every single one on a grid point. Just the ones that are significant to defining the form of your mesh. For example: On my arch, the vertices that define the form the most are the ones that make up the top and bottom edges. The ones in between aren’t so important.

Shape reference

In order to make things slightly easier, I’m going to make a duplicate of my object that will act as a shape reference for my final piece.

Go into Object Mode (TAB). Hit SHIFT-D to duplicate, then RClick to place the duplicate mesh at the same location as the original. Now go back into Edit Mode (TAB again).

In this image, I’ve pulled one of my ‘significant’ vertices down so you could see the reference line provided by the duplicate mesh.

What I want to do is place the vertices at points on the grid that intersect with the reference line (like the point marked with the yellow arrow.
Do this for all your significant vertices.

In the end, your mesh may look something like the image on the left. I have marked all of the vertices which I placed on the grid. All other vertices shown were placed arbitrarily.

Now, snap your vertices to the grid, then bake your sculpt map.

The vertices kinda look like a mess, yeah, but in the end, you keep the shape of your object better than if you had left your mesh in it’s original state. To emphasize my point, and also show off what precision sculpties can do, here is a screenshot of my finished sculptie in Second Life, below it’s closest equivalent made with regular prims. You can click the image to see it larger:

Tricks, Tips, and Notes

I’m still learning about precision sculpting, but as I gain tips and tricks for making precision sculpting better and faster, I’ll add them here.

Trick: Mirrored Halves

If you have a precision sculpt that has symmetrical halves, you can cut down on some of the placement work by using a mirror modifier. (Click here to learn how.)

With the mirror modifier in place you can go through and place the vertices on the one half of your sculpt, and the modifier will do the other half for you.

Note: After you’ve applied the modifier, you will have to move the vertices on one half inward by one grid space  so that the sculpt’s dimensions are still 2.55 units cubed. Now snap your vertices to the grid, then export the sculpt map.

Tip: Default Settings

If you find that you’re using the precision grid very often, you can add the grid to your Default Settings. Just set everything up how you want it to look when you open up Blender, then navigate to File > Save Default Settings.

Note: Shrinkage Resolution Trick

If you’ve already read my tutorial on Resolution Tricks, you’ll probably remember the section on shrinking a sculpt. When you do this, you are giving up a chunk of your possible placement points.

For example: If, in the Levels dialog, you put the sliders to 50 and 205 (default is 0 and 255) You are taking off 100 possible placement values for each axis. If you know you’ll have to do this resolution trick, plan ahead. Instead of sizing your mesh to 2.55 cubed, you’ll have to size to 1.55 cubed.

Starter 4: Get Familiar With Multires and LOD

 MV-SL-Tutorials, Start Sculpting, Tutorials  24 Responses »
Mar 072010
 

Multires!

In older versions of these tutorials, I introduced LOD and multires in a short section in the previous tutorial. However, with the new Primstar scripts, I’ve decided to create a separate and more detailed tutorial on this rather important topic.

LOD

LOD stands for Level of Detail, and refers to a function of Second Life, OpenSim, or any other game where a mesh becomes less detailed the further away you get from it. This is important in games as it helps decrease the resources needed to render the game’s graphics.

Multires

Multires is an option inside Blender that lets you switch to lower levels of mesh detail, which corresponds nicely with Second Life’s LOD.

To make… a box.

There is a certain set of video tutorials that explain multires by having the viewers create a box. Although a box might be a silly example, it serves the purpose, and it introduces some useful editing techniques.

So I’m going to use the box example, but with a few variations that I think make it easier. So go back into blender. Delete your old sculpt, and if you’d like, save the file as something new.

Now create a new sculpt mesh. Make it a cylinder with multires subdivision, just like the previous one. In the Edit Buttons, click “Set Solid” (marked in green) to give the mesh sharp edges instead of smooth ones.

Now switch to the top view (NUM7), go into edit mode (TAB), then deselect everything (A). Then with the Box Select tool (B) select the bottom part of the circle, like the first image below. Then, making sure proportional falloff is OFF, press S to scale, Y to scale along the Y axis, then press 0, then ENTER. You should end up with a straight line of vertices, like the second image below.

Now select some vertices on one side and press S, X, 0 to make on of the sides of our box. Keep doing this until you have a square or rectangle that looks something like the third image above.

Now lets also cap off the top and bottom. To do this, go to the front view (NUM1) and select the top and bottom edge loops. Then press S, SHIFT-Z, 0. This scales everything except the Z axis down to a point.

Then make sure the top a bottom are flat. Use the Box Select tool to select the top point you just made and the next edge loop and scale Z to 0. (S, Z, 0) Do the same for the bottom.

Note: To anyone with OCD, I apologize for my terrible box. As you can see, it isn’t very even. I did this on purpose, though. Lets bake this sculpt and upload it to the grid.

Tada! Up close, this cube looks pretty good, right? But as we zoom further away, the corners start doing weird things. You’ve probably seen similar behavior in a lot of sculpties in Second Life. (Though hopefully not on anything as simple as a box!)

So what do we do about it?

A Better Box

Go back to blender and in Edit Mode, find the tab labeled “Multires”. If you look for the ‘level’ button, (marked in green) You’ll see that currently, you are on multires level 3.

What does this mean? Well… click on the left side of this button to switch to level 2, then level 1. You’ll see your cube lose a lot of its vertices, and as you can see from the picture on the left, my cube no longer looks like a cube. It looks exactly how it looked in world when I zoomed out.

So what would happen if I made it look like a cube at Multires level 1? Lets do that.

I even decided to line up the middle vertices to make it look pretty. Anyway. Lets switch back to level 2.

Woah. Hey what happened here?

Well, Blender multires likes to help “correct” your mesh if one multires level is very different from another. Level 1 may have been that perfect box, but level 3 was still the old box, so Blender tried to create a “happy medium.”

In a lot of cases this behavior is what you want, but sometimes, especially with geometric shapes, you don’t want this at all.

So… lets fix this. Hit CTRL-Z to undo, going back to our nice level1 box.

Now since Blender still thinks multires level 3 and 2 should be our old box, the easiest way to fix it is to delete the higher levels. In the multires tab, find the button called “Del Higher” (marked in green) and click it to get rid of the higher levels. All of the options below should vanish. Next, click on the drop box currently marked “Catmull-Clark” and switch it to “Simple Subdiv.”

What does that mean?

The options in the drop box are different methods of subdividing a mesh. Simple subdivision adds vertices by dividing each edge exactly in half. This is good for meshes with a lot of straight edges.

Catmull-Clark is fairly well-known algorithm developed by Edwin Catmull (of Pixar) and Jim Clark (see Wikipedia). I don’t know the technical details of how it works. Only that it’s currently the best algorithm for smoothing a mesh.

So with Simple Subdiv selected, click “Add Level” twice, and you should get something that looks like this from the top.

Now if you bake the sculptie and upload it to the grid, you’ll have a cube that holds up well, even at a distance.

REMEMBER to upload your sculpt map with “Lossless Compression” checked!

Personally, I’m feeling lazy, so I’m not going to upload it.  _I_ know it would hold up.  You’re probably convinced too, and I don’t really have any practical use for this sculpted cube.

Don’t consider the time wasted, though.  You’ve learned some valuable skills and a VERY valuable lesson. Right?

Just in case you need a reminder, here it is again:

The moral of the story, and some tips

The box held up better when built at a lower multires level, and the same is true of ALL other sculpties.

If a sculpt is simple enough, like most organic shapes, I’ll start sculpting it at multires level 1. For more complex sculpties, like furniture, I’ll start with multires level 2. I never, ever, EVER start with multires level 3. Sure, you can make really complex sculpties at that level, but if your object turns into a birds nest when you walk three feet away, it’s not really worth it.

START WITH A LOWER MULTIRES LEVEL.  This ONE principle leads to better LOD and cleaner meshes.  While there are other tricks that can help along side it, nothing can substitute for it.

Tips:

Working from a lower multires level is actually useful for more than just LOD. It lets you establish the basic shape of a sculpt while you have less vertices to worry about. Ultimately, this can help you create a cleaner sculptie.

Sometimes adding a multires level with Catmull-Clark subdivision will smooth out a sculpt too much for what you need. When this is the case, try using Simple Subdivision, then click the “smooth” button in the Mesh Tools panel to round things out a little. This also works if only part of the mesh needs to be smooth. Just select the vertices you want to round out and click the smooth button a few times.

Starter 3: Create Your First Sculpted Prim

 MV-SL-Tutorials, Start Sculpting, Tutorials  40 Responses »
Mar 072010
 

Start Sculpting!

This tutorial assumes that you already have Blender, python, and Primstar installed.

It also assumes that you have learned how to move the camera in Blender, and the use basic editing hotkeys (Grab, Rotate, and Scale, along with the X, Y, and Z constraints).

If you haven’t done either of these, check out the previous tutorials:

Starter 1: Installing Blender and PrimstarStarter 1: Installation
Starter 2: Blender 3D Basics

Open up Blender, if you haven’t already, and lets get started.

Split Screen

Before we go too far, I’m going to have you split your view area.

Hover your cursor over the edge between your 3D View area and the top menu. When your cursor changes to the double-arrow resize cursor, right-click and select “Split Area.” (Click the image on the right to enlarge.) Then place the split line somewhere in the middle of your 3D View division. You’ll now have two identical 3D Views.

Of course, you can change the angle of each division separately now to see different sides of your mesh at once, however, you can also change the divisions to show something else entirely.

On the bottom left of each of your 3D views, you will see a tiny menu with an image that looks like a grid. If you click it, it will give you a list. You’ll see that your current division type is named ’3D VIEW’. Oh my gosh.


Most of the other types are irrelevant to sculpties, but I want you to change the right division from the 3D View, to the UV/Image Editor. Right now there isn’t anything in the UV/Image Editor, but this window will probably become one of your best friends in the long run. This division setup is actually very common for making sculpts. Eventually you may want to make it part of your default settings.
You may notice that EACH division has that same menu. The default division on the top is named User Preferences. The default division on the bottom is the Buttons Window.

Adding a Sculpt Mesh

Right now, everything in your 3D space is useless for making sculpts. Tap A once or twice to select it all, and tap the delete key to get rid of it.

Adding a sculpt mesh to our 3d space (or scene) is made ridiculously easy by the Primstar scripts. With your cursor in the 3D View, tap SPACEBAR, and then go to Add > Mesh > Sculpt Mesh.

If “Sculpt Mesh” is not an option in the menu, then chances are that the Primstar scripts didn’t get installed properly. Read the Primstar documentation for more information, or go to their website and ask for help on their forums.

You’re then presented with a dialog. Click on the Shape field to choose which shape you want to start with. For this tutorial, start with a Cylinder).

There are a lot of other options for your sculptie. For now, I want you to change Subsurf to Multires (marked in red). Check “default” and then click “Build”.

In previous versions of this tutorial, I had users get rid of the subdivision (or ‘multires’) levels. This does not work with the new Primstar scripts, as the number of faces and multires levels determines the size of the sculpt map created for your mesh in order to support Oblong Tessellation.Because of this, and because I wanted to add more detail about the intricacies of Multires, I decided to address that topic in a separate tutorial.

Edit Mode

Blender works in several different modes. Luckily you only need to know about two. You are currently in Object Mode. You can only select entire objects in your 3DView.

The other mode we need is Edit Mode, which will allow us to move individual vertices on our cylinder. Tapping the TAB key toggles between Object Mode and Edit Mode. Switch to Edit Mode now.

The lower division of your screen is the Buttons division. The menu of the button division lets you look at different button sets, depending on what you want to do. Tap F9 or select the Editing button in the Buttons menu if you aren’t already looking at the Edit buttons.

Lets also turn off that annoying axis thing by clicking this hand icon:

Selecting Vertices

You’ll notice that you can select individual vertices by right-clicking, and you can also shift-click to select additional vertices. But there are other selection tools that make selecting a lot of vertices very easy.

Press B once to start Box Selection mode. Your cursor will become a cross hair, and you can click and drag to define an area to select.
If you press B twice, you’ll start Brush Selection mode, which will change your cursor into a circle that you can use to ‘paint’ your selection. You can make your brush larger or smaller by using your scroll wheel.
Finally, if you hold down ALT and right-click on one of the lines (or edges) of your mesh, you can select an edge loop.

All of these methods of selecting vertices will be useful while you’re forming your sculptie.

Proportional Edit Falloff

The next thing you will want to know about is Proportional Edit Falloff, as it cuts down on a lot of work.

Select a few vertices using whatever method you’d like and press G, R, or S, to manipulate them. Notice how, by default, Blender only moves the vertices you have selected. We can change this default behavior by using Proportional Falloff.
Depending on your screen resolution, the Proportional Falloff icon may be hidden because of the split screen. Use the mouse wheel to click on the 3D View menu and drag it to the left until you see the icon.

Find the icon that looks like a donut (shown above) and select either On or Connected. (All of our vertices are connected, so either mode works the same.) You’re now presented with another menu, but we’ll play with that later. Make sure all of your vertices are deselected (tap A) and then choose one vertex on one edge of your mesh. Tap G to grab and watch what happens! Now try R and S.

You can change the area size that the falloff effects by tapping Page Up or Page Down.

Now fiddle with that other menu to the right of the falloff button.

Now select an entire row of vertices by using the Box Select tool, or Alt-Right-Click on a horizontal edge. Now scale (S) to see what happens. Try making a chess piece or a table leg.

After you’ve finished your mesh, we need to convert it to a sculpt map image. We’ll be doing this by using the Primstar scripts.

Baking

Before we get any further, you should rename your object to something meaningful. I’ve marked in yellow the Object name field on the image to the left. Click on the image to enlarge it.

Your object is probably named something like “Cylinder.” I’ve already renamed this mesh to “pawn.”

I have to admit, I often skip this step, but naming your objects has a lot of advantages.  For one, if you name the object, the Primstar scripts will automatically name your sculpt map by the same name. It also helps with organization later, if you have a file with many different objects and you need to keep track of them.

The Bake Script

Anyway. Go to the top menu. Select Render > Bake Sculpt Meshes (marked in red). You’ll now be presented with the Primstar bake dialog. There are a lot of options, but the defaults should be fine, so just click the Bake button (marked in yellow).

You should now see a rainbow image in your UV/Image Editor division.

Now all you need to do is save the image. In the UV/Image Editor menu, go to Image > Save As. (Marked in green.)

Browse to your desired save folder and save the sculpt map.

Importing into Second Life (or other Grids)

Log into Second Life, or your grid of choice and go to File > upload image and select your sculpt. In the preview menu, select Preview as: sculpted prim, and it will show you a preview of your sculpt. If something looks wrong and you can’t figure out why, contact me.

These screenshots were actually taken in a grid called Avatar Hangout. Uploads there are free, which is convenient for tutorials. (And for experimenting! I recommend finding a grid with free uploads if you want to try things out without spending money.)

Anyway. build a default box on the ground somewhere. Make sure that you’re seeing the advanced tabs (click on More>>), then go to the Object tab (marked in green). Now change the Building Block Type to Sculpted (marked in yellow). Now you can replace the default sculpt mesh with the one you just uploaded.

This is my sculptie imported into the grid. Notice it looks pretty much exactly as it did in Blender up close, but as I zoom away from it, it loses a lot of detail. This is referred to as LOD. With Blender, we can actually have almost complete control over how these different detail levels look. So lets go on to the next tutorial: Multires.

Starter 2: Blender 3D Basics

 MV-SL-Tutorials, Start Sculpting, Tutorials  10 Responses »
Mar 012010
 

Blender Basics for Second Life Sculpties

It was a grand occasion one summer day back in 1997. I was an ambitious 14-year-old who wanted to get a head start in 3D modeling. I had installed Blender 3D for the very first time on my computer, and had just opened it up. What I saw was something similar to the image on the left.

What did I do from there?
I stared at the screen for two minutes before shutting down Blender and going back to playing video games.

The moral of the story is: Blender is complex. I will not lie here. However there is GOOD NEWS for you Second Life sculptors.

The news is this:
You don’t have to learn all of Blender to make sculpties and what you need to learn is PRETTY EASY!

You should already have Blender, Python, and the Domino scripts installed. If not, back up one tutorial.

Also, in order to make life easier, you should have a full-size keyboard with numpad, and a two-button mouse (preferably with a scroll wheel). If you are using a laptop keyboard, either buy a full usb keyboard, or at least a usb numpad. If you’re using a 1-button Mac mouse, I’d recommend getting a cheap mouse from Wal-Mart or something, but you can use the typical mouse/keyboard combinations if you feel so inclined.

Blender Windows

Blender’s interface uses a rather unique window setup. I won’t get into the complex details in this tutorial, but I need to explain a few things.

When you first start up Blender, you will have three divisions, or windows (Shown here. Click to enlarge).

So how is this important to you right now? Your cursor’s location determines which division is ‘active.’ The active division will respond to all mouse and keyboard commands, so if things on your screen appear to be unresponsive, first check your cursor position.

Blender Camera Controls

The NUMPAD is your friend for camera control. If ever you don’t know which way you’re pointed, just tap 1, 3, or 7 on your numpad and it will show you the front, side, or top respectively. If you ever need to see opposite side of your sculpt, simply hold the CTRL key in combination with the numbers.

The numbers at the top of your keyboard don’t control your camera. Instead they switch between ‘layers’ in Blender. If you press one of these keys, your mesh may disappear. Don’t worry. Just press 1 at the top of your keyboard to return to layer 1.

Your mouse wheel is your other camera controller. Scrolling with the wheel predictably zooms in and out on your 3D view. Clicking and dragging with the wheel will rotate the camera around a set center point. If you hold SHIFT while clicking and dragging with the wheel, the camera will pan along the current view plane.

Remember: If your view doesn’t respond to the keypad, check your cursor position.

If you have no mouse wheel, there are alternate camera controls:
ALT+LClick/Drag — Rotate
ALT+SHIFT+LClick/Drag — Pan
ALT+CTRL+LClick/Drag — Zoom

Basic Editing in Blender

Before we get into making actual sculpts, we need to get familiar with the basic editing hotkeys. They are fairly straight-forward.

Selection:

Right now, you have three objects on your screen. A box, a camera (pyramid thing), and a light (circle-thing). To select one of these objects, Right-Click on it, and it will get a pink outline. To select more than one, SHIFT+Right-Click on each in turn. You can also SHIFT+Right-Click on a selected object to deselect it.

To toggle between selecting ALL objects on screen and NONE of the objects on screen, tap the A key.

Object Manipulation:

The hotkeys for basic object manipulation are really straight forward.

G – grabs the current selection (picks it up so you can move it)
R – rotates the current selection
S – scales the current selection

Tap one of these keys ONCE. This will only begin a rotation, scaling, or move. At this point, your manipulation is ACTIVE. Left-click to set the manipulation or Right-click to cancel it.

Also, you probably noticed that S will scale your object in all directions (every axis). If you want to scale in only ONE direction (axis), while scaling is ACTIVE, press either X, Y, or Z. These represent your X, Y, and Z axes. Also, if you press SHIFT + X, Y, or Z you can scale in all but one direction.

Blender also allows you to use the X, Y, and Z modifiers while grabbing (G) and rotating (R) your selections. Try them all out to see what they do.

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