Simple, perfect sculpt shapes in Blender?

I've been using Blender to create sculpted prims since they were introduced, but I've always stuck to a 32x32 sphere and never gave it much thought until recently.

I loaded up Wings 3D and tried a few other starting shapes from templates. A 8x7 sphere, 16x15 and so on. The end results looked very nice, they produced less complex sculpts (fewer faces) with perfect geometry in world, just as good as normal prims, without the bumpy sides or distorted poles, as you can see here:

http://tinyurl.com/2dm32v

However, attempting to recreate the same shape in Blender gives me a 32x32 object in-world regardless of the starting shape. I've tried a few things and am thinking it's due to the "blend" setting for the textures, giving it gradual progression to the next color instead of the sudden changes produced with the Wings 3D sculpt texture. I've tried other settings but what I need does not seem to be offered. Though this may not even be the problem.

http://tinyurl.com/2a8xun

Examples of the end results are here:

Wings 3D shape:
http://tinyurl.com/2z2wg3

Almost exactly the same shape baked from Blender:
http://tinyurl.com/26qvpf

and side by side in-world, with the poor Blender mesh on the right:

http://tinyurl.com/25g6eu

Perhaps I'm missing something simple, but is there a way to get the same result in Blender? I think this would also possibly eliminate the general in-world bumpy-ness often seen in Blender sculpts I've made that are otherwise perfect in the program itself.

My actual .blend file in question is here:
http://rapidshare.com/files/65891562/Basic_Sphere.blend

Thanks.

There's absolutely, positively, no way to make a sculpty in-world with anything other than 1024 vertices, which means all sculpties ALWAYS have the same number of faces (2048 tris). If the Wiings exporter is producing sculpties that look like they have less, then I'd have to conclude it's simply overlapping vertices on top of each other. The "missing" faces are all still there; they just have no dimension to them so you can't see them. Hopefully someone with more exptertise on Wings, like Daniel, can chime in to confirm this. I can't think of any other explanation.

If you want to acheive similar results from Blender, you probably could by overlapping vertices by hand. However, since you're really not saving any polys by doing that, I can't imagine why you'd want to. The only real benefit in overlapping vertices is it will make your objects more LOD-resistant, but that doesn't seem to be what you're after.

If your goal is to make sculpties with less actual faces, you'll have to wait for LL to decide to allow user-definable mesh sizes, or at least a broader selection of preset sizes than just the one we have now. We're all hoping they will make the right decision on that, but the jury's still out, and likely will be for a good long time yet.

You can have up to 1089 unique vertices in plane mode.

As for the weirdness in Blender, I'll let Domino cover that, as I have had blender open for a collective total of ten minutes.

Let me try to reconcile Chosen's and Daniel's observations about vertices.

You can make and upload sculpt maps of different sizes and shapes. If you have a model that is accurately expressed in a 4x16 bitmap, for example, you can upload that into SL. (You probably won't want to use the SL client for that yet, just because of JPEG compression problems.)

Inside the client, when the sculpt map is getting converted to geometry, the client will re-sample the bitmap and produce a square mesh. At maximum LOD, this mesh will always have 33x33 vertices. At lower LOD, it will be 17x17, 9x9 or 7x7. In the process of converting the bitmap to this mesh, vertices may be either dropped or duplicated -- whatever is necessary to get the desired mesh size. This mesh is what Chosen was referring to, although I'm not sure why he said 1024 vertices in his post. I suspect that he was thinking of the maximum LOD and the 1024 instead of 1089 was just a slip.

But this still isn't the whole picture. If vertices get doubled up in constructing the mesh, there will be degenerate faces at this level, as Chosen described. But there are more steps in the graphics pipeline, and some of those degenerate faces seem to get removed somewhere. I haven't figured out the whole process yet. When I asked Qarl about it a few weeks ago, he thought some of them would get optimized away, but wasn't sure. (If he didn't know off the top of his head, I don't feel too badly about not having it all figured out yet.) But I do know that my testing seems to show that not all sculpties have the same effect on frame rate. I say "seems to" because I haven't found a really reproducible test for making solid comparisons.

As to why Wings preserves the exact shape of your model but Blender doesn't -- the Wings' exporter is much more simplistic than Blender's. The Wings' exporter directly maps model vertices to bitmap pixels, so the results are very predictable. Blender goes through an intermediate process that gives it the capability to handle a wider variety of models, but the downside is that it can be more difficult to get precise control when that is what you want. But as Daniel says, I suspect Domino will post on how you can get the same result from Blender.

From the brief look I had at the SL source code, there is duplicate triangle and degenerate face removal in the sculptie pipeline. I noticed the comments in the source for it but didn't investigate how it worked. As the wireframe view in SL would look the same with duplicates or with them removed, the code is the only way to know for sure. It's on my todo list to have a better look.

As far as Blender is concerned, yes it does interpolate between points. This was to allow non standard meshes to generate full sculpties. If you want to avoid this then bake the sculptie to a lower resolution image and scale the map in a graphics app with no interpolation.

Also you might want to grab a copy of my Blender scripts, it's a lot easier than messing with materials for the bake: /8/60/203571/1.html

There's demo/tutorial videos for the scripts here: /8/ab/210627/1.html#post1677452

Generally bumpiness comes from not having the UV map aligned with the available points. I made this grid to help check that.

http://dominodesigns.info/images/sculptie_grid.png

Just load into the UV Image Window and see how things line up.

I'll see how that goes! As for the bumpiness, they've always been perfectly aligned .

Update: The image scaling thing worked great, no real need to scale them up either as they turn out fine. That will make for a quicker download time I guess, always a good thing.

Thanks!

Vaelissa, great to hear that you got it to work. Now can you give me (a Blender noob) step-by-step instructions so I can do it too?