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.
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.
I was unable to get the straight sides of the box in the first step. I reset all defaults to factory settings (figuring I’d screwed up some setting or other), and repeatedly followed your instructions. What I ended up with for the distribution of vertices was . . . well, the best way I can describe it is like the letter Y, with very long arms and a very short base, and it seemed that all the points were gathered in the base. When I looked at it from the front and rotated, it, it looked like there was a crimp on one side that protrudes from the old conture of the cylinder. Does this make any sense to you?
<_< Not at all. You might want to take a screenshot and post in the forums. I'll be able to help you better that way.
Murgy – thanks so much for putting together these wonderfully done tutorials. I’ve been pretty lost until I came upon your site.
I have a question. When I use the spacebar and Add > Mesh > Sculpt Mesh, I get a different dialog box than what you show. My dialog box has Mesh Type X Faces 8, Y Faces 8, Subdivision Lev 2, Use Subsurf and Clean LOD’s. There is no Multires, nor any choice of sizes.
I have Blender (2.49b) on a Windows XP computer and I have downloaded the latest Primstar scripts version (primstar 1.0.0.zip).
What would be the problem? Thanks much.
It sounds like you had an older version of the primstar scripts installed before you installed 1.0.0. Either find and delete the old scripts or delete the entire scripts folder and reinstall Blender and Primstar. Whichever is less hassle.
Thanks Murgy. That must have been the problem. I uninstalled everything and then re-installed. It works great now.
(I did make the mistake of copying the Primstar script files to the Blender script folder — instead of copying the Primstar directory — and for a while I was puzzled why I was getting a console error. But finally I realized the problem and the errors disappeared.)
Thanks again for your time in putting together these great tutorials!
Hello. TYVM for your useful tutorials.
Following this one , I totally get lost when you say “I even decided to line up the middle vertices to make it look pretty.” …….so I am not able to do last steps.
My apologies for my crappy english.
I mean the points between the corners (the ones that are highlighted in screen shots).
If you made the cube better than I did in this tutorial, it’s likely that those points are already lined up. I was being messy for the sake of being a bad example.
Very good tutorial. Thanks for sharing your experience in blender.
But I have a doubt about lod …
I made a diamond with level 1. The diamond remained with its format, but in SL it was cut (faceted). Diamond was smooth.
can you help me please.
Thank you very much:))
Hmm. If there was a difference between what you had in Blender and what you got in SL it might be that you didn’t check your multirez level 3 before you baked your sculpt map.
If that isn’t it, you might have to show me exactly what you mean by “faceted”. Could you sign up for the forums real quick and post a screenshot of sculptie both in Blender and in SL?
Sorry!
I do not have options for accessing the forum
Erk. Seems that updating the site took off the link to the forum page. Lemme see if I can fix that. In the meantime, the forums are here. http://robynhuffaker.com/sculptblender/forums/
Thank you very much for your tutorials, they have been a big help and are very enjoyable to boot.
Hello Murgy. First, i would like to say many thanks for this site and the tutorials especially. I spent 2 months trying to understand Maya, and when I finally got some results, the sculpt did not look the same in sl.. not talking about the thing which I now know is caused by the multires thing. Yesterday, I spent 4 hours reading your tutorials, and today I feel I could have some results
Except that it is all in one place her, in my opinion the way you describe things is really comprehensive and easy to understand. So once more, thanks again.
I would like to ask about the multires thing in more detail (I was trying to use the forums, but the reply button seems to not work for me). While I understand the principle, which is in my opinion something like zoom out in sl = lower multires, zoom in = higher multires, i dont understand in detail how it is possible to take precise advantage of the knowledge. I am trying to sculpt relatively complex sculpts (well, to me it seems so at least), but i would like them to appear good from distance in sl without having to change the rendervolumeLOD (which in my opinion cant be expected from people, who just want to have fun in sl). Meanwhile, I would like them to appear nice and detailed from short distance. So I thought, I edit the levels separately. But this idea was obviously wrong
What would you suggest me to do to achieve this – looking ok from distance, while detailed from short distance.
Thanks in advance.
LOD for Sculpties is a little different than other games in that, there really isn’t any separate mesh information from one level to the next. It’s still reading the data from the same sculpt map image.
When a sculptie drops a level of detail, all it’s doing is taking out every other edge loop on the sculpt map, and leaving the rest.
So its not like you can add a whole lot extra features onto your sculpt with the higher levels of multires. You just.. do the best you can at a lower LOD level, then use the highest level to smooth things out or add little creases and things.
Wow, I believe I would not get such a fast answer if I emailed my issue to some kind of a paid customer service
Well, I am not a games creator or nothing like that. I just enjoy to be creative in my free time, and sl seems to be a good way to show the creations. And well, I am a bit picky about the detail.
So if I get it correct, the best way to do that is to create the object on a lower multires, then add another, finetune it a bit so that it does not affect the previous level too much. Since I suppose the final sculpt map image is done based on level 3. Which makes me actually wonder what if I dont add the multires 3, but well, I can do a test of this by myself as well
I am also trying to create precise sculpts (again based on your tutorial), but somehow I cannot get the grid big enough – it does not allow me to set more than 100 lines.
Last thing I would like to ask you if you know what prerequisite needs an object imported to Blender from other file formats (like eg. *.obj or *.max). I was unable to bake the texture (bake failed). I suspect it has something to do with the number of faces, or shapes of them, respectively a “perfect UV map”, which I am not sure I understand what is… although was trying to do a google research on it.
Sorry if my questions are too begginerlike, I hope it does not bother you too much
Thanks again.
Well it all depends on what is acceptable for the job. If you read the tutorial on maintaining LOD, you’ll read that larger objects maintain their LOD at a longer distance than small objects.
Sometimes I’ll actually start modeling at multires level 2. Especially if I’m making furniture, which is a decent size and also people tend to prefer furniture that’s low-prim so they can put more on their land.
For precision sculpties, the grid floor size doesn’t matter that much. From x,y, and z plane views, the grid will extend indefinitely.
As for making normal meshes into sculpties, the prerequisite is that the objects must be build it sculptie format. Most conventional meshes do not fit the sculptie format. If the mesh wasn’t made to be a sculptie, chances are you won’t be able to use it.
Hello Murgy,
I got some grip on this thanks to your web …still getting familiar that there is a shortcut for everything instead of a button
However, I build a common 8point star from a sphere using the oblong tesselation 16×4, started at multires 1 with simple subdiv. Everything went fine, and as for the star it is ok. Just when i zoom out really far in SL (using the default rendervolumeLOD), the star becomes a circle (or a sphere probably). There is some improvement if i use the resolution trick, but it does not look fine when zoomed in. Is there something like multires 0, or it is just impossible to make it appear ok also from a real big distance? If my description is not clear enough, I can send you the blend file somewhere, but I really dont want to bother you too much.
I also googled around the import possibility. There is a way to import *.obj files, but the uv map is not what is possible to use for sl. I am trying to export from maya, which has the option to export an *.obj file and has also many other functions, which could be possibly used to convert the uv map the way it is neccesary, just i really dont know where to begin regarding the uv map.
Thanks for your time
There is actually a SL LOD level below the typical “level 1″ used by most sculptie artists. Usually most people don’t bother about it there’s not much you can do with it, and some of the oblong sizes can’t work well at that LOD no matter what you do.
If you use the square sculpt map, you can replicate the lower LOD level by making your mesh 4×4 with three levels of multires, but if you think about oblong tessellation, you’d have a size like… 2×8. And you can’t really have much of a 3D shape with only two faces.
As far as the .obj thing is concerned, if anyone’s said anything about being able to import .obj files, they were talking specifically about importing them into Blender. Not Second Life. SL doesn’t yet support mesh importing. The Primstar scripts do have a .obj-to-sculptie importer, but even that is designed to import meshes that were made TO BE sculpties. If the mesh was not made to be a sculptie there is a 99% chance that it CANNOT be a sculptie.