Precise control with sculpties in Blender

I'm new to Blender, and I've seen a few tutorials for making sculpties in Blender, but what I would really like is instructions on how to use Blender to make sculpties with precise control of each vertex as it ends up in SL (at max LOD). As I understand it, in some other software, the sculpty exporter correlates each pixel to a vertex? Or something? But I guess Blender doesn't do that? Well that's what I would like. So I need to know how to make sure I'm starting with the right number of vertices (1089?) and how to make the resulting sculptie texture translate those vertices precisely into SL. A full-on tutorial with pictures can be a pain to make, I know, but I'll be happy with just text instructions, as long as they are written at "noob level".

Well try not to get so lost as to end up thinking that Blender ultimately does anything any differently.

Here's what control you do and don't have (regardless of 3D modeling program):
—No control (yet) over how many quads(=paired triangles) your sculpted shape has. They're all 32×32 = 1024 quads = 2048 triangles. You can effectively erase some triangles by putting multiple vertices on the same, identical location, which also makes that edge look sharp.
—The ability to place each vertex in the X, Y, & Z dimensions (from R, G, & B channels respectively) with 8 bits of info for each dimension. 8 bits = 2^8 = 256 different positions along each dimension.
—Though this feature isn't fully supported yet, in-world, you get the power to select the wrapping mode of the default "sphere", or "cylinder", "torus", or "plane" (currently only through a simple LSL script command). The only difference between them is how the edges connect (or don't connect) to each other, and consequently, exactly how many vertices are needed to make those quads. The "cylinder" ties the left side (of the image's pixel-vertices) to the right side, but leaves the top and bottom open, so it gets 32 vertices horizontally × 33 vertices vertically. The "sphere" is the same except that it makes the top and bottom close up together like poles. The "torus" ties the left to the right and the top to the bottom, so it needs only 32 × 32 vertices. The "plane" leaves everything untied, thus needing 33 × 33 vertices.

—And one question that really leaves some wondering: "HOW DOES AN EDITOR POSITION 33 VERTICES INTO AN IMAGE?" It's a very good question; you can't really upload an image 33 vertices across (as dimensions are always a power of two)! Qarl Linden's answer: Use a full 64 pixels, placing the first vertex at pixel 0, the second at 2, the third at 4, and so on... until after the 32nd vertex at 62, you have only one position left – pixel 63. Place the last vertex right there.

I hope my explanation made perfect sense. Every time I referred to "a position", I meant a single notch along an individual dimension, trying for the sake of simplicity to describe only one dimension at a time.

And I know I might not have answered the question, but I just want to be sure you understand how all sculpties are the same. (You weren't more specific as to what it is you don't understand.)

Your explanation is pretty good, though still leaving some things unanswered. I guess what I was talking about is that some other threads mentioned that the maps generated by Blender use some sort of interpolation... or something... instead of a direct correlation between pixels and vertices as generated by some user-created plugins for other software like Wings. But another thread did mention that you could get that correlation in Blender too if you did... something... about the resolution of the uv map? And start with the right mesh? Anyway what I'm looking for is step by step instructions for Blender.

Ahh. Well then, I suppose the interpolation you heard about has to have only been part of some Blender plugin's feature. I know somewhere around these forums you're able to just download the sculpty-ready sphere and cylinder, along with a Blender-to-SL script, then reshape their vertices directly, and save them rather simply to sculpt maps. Now where exactly were they... *looks...* (okay so I'm not really a Blender user either.)

I have seen the cylinder and sphere you're talking about. But I wasn't sure using them would be any different than starting with any other mesh of any random number of vertices (which apparently you can do in Blender and still use it for sculpties, I think).

Glad you found them, because I didn't (got bored, then wandered off) . To start from them, if you're comfortable with it, is logically a whole LOT better than starting from anything else, because ultimately everything you make has to be converted INTO (a deformation of) one of them (unless you're using the Plane, which is only ever-so-slightly different as I said before (or the Torus, but the cylinder will really work just fine for that)). That conversion is exactly what the bigger plugins employ complicated tools just to accomplish, because a lot of builders want to work with NURBS and other smoothly-flowing modeling techniques rather than individual vertices.

The Blender scripts that do the interpolation just do it inbetween vertice. The pixels under the vertice get the exact position. This is so you can model low detail and still get pretty good spacing for texturing. With one of the blender files from my starter_sculpties pack, what you model in Blender is what you get in Second Life as the UV map is already setup for the full 33 x 33 vertice grid

See the Blender importer thread /8/60/203571/1.html for downloads