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.

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.