Sculpties for Dummies questions

So I've found lots of resources on advanced sculpting and programs. But I haven't found a generic, basic, "I've just picked up the game and I want to sculpt" tutorial. Is there one?

A more specific question: When starting with a sphere in a modeling program to bake a sculpt map from, what is the maximum number of vertices you can use to create the sphere in a modeling program? I've heard 64 and I've heard 124.
Also, I understand that the maximum and ideal sculpt map size is 124x124 pixels?

Any help would be greatly appreciated. =3

THE simplest ones are Rokuro and Totoroken, but the latter is for PC only. You can turn out limted kinds of sculpts in about 5 min.

Well, yes and no. There are many different sculptie tools around these days. Each of them comes along with different levels of complexity. Rokuro sounds like one of the simplest solutions, but when i tried it a while ago, i found it very very limited and not usefull for my purposes.

Wings3D sounds simple to use, but i never used it. I also do not know, if good documentation for this tool is available.

I personally love blender, although people declare it as the most complex of all tools. Maybe because of the learning curve or the unconventional userinterface?

Anyways, the machinimatrix has created a whole set of tutorials for sculpties, which may be of interest even if you do NOT work with blender. many of the principles we are introducing are tool independent. So you might give it a try:

http://blog.machinimatrix.org/video-tutorials/



There is a standard size for sculpties: 32*32 faces (33*33 pixels -> 1089 pixels) This was the only supported size for a long time. Recently other x/y ratios have become available. But so far as i know, this is only available in the RC-viewer at this time. But beware: The highest number of pixels per sculpty has NOT increased, so whichever ratio you try out, you will always get 1024 faces at maximum. Smaller maps and odd ratios are possible.

Now for the size of the sculptmap:

First to know: The size of the sculptmap and the size of the image in which the sculptmap is transported is different!

In old days, when every sculptie was 32*32 faces in size, the viewer simply sized any incoming image in such a way, that it fits to a 32*32 faces sculptmap. And this gave trouble if you did not take care. Especially as the pixel size is 33*33 (see above) you can not simply load a 32*32 pixel image map and hope that your sculptie will look as expected in all circumstances...

Linden was aware of this extra pixel per dimension and they have optimized for 64*64 image size. Whatever you give to the viewer, it will be transformed to a 64*64 image before it is interpreted as a sculptie (Not sure, if it is realy done so, or by an equivalent algorythm, but the net effect would be the same).

Nowadays, where different ratios are available, the SL-viewer must conclude from the image size which sculptmap size is intended. So the rule is now:

if you want a ratio X/Y then you must provide an image of size 2*X/2*Y
How the pixels map to the sculptmap in full detail ? I dont know exactly, but all
sculpty programs should take care of the creation of the sculptmap behind the scenes
anyways.

From my experiments sculptmap ratios can be:

mapsize -> image size
32*32 -> 64*64
64*16 -> 128*32
128*8 -> 256*16
256*4 -> 512*8
512*2 -> 1024*4

odd ratios are available (not mentioned here)

I hope, this gives you a bit of a help. BTW: Where from comes this information about 124*124 pixel ? That does not sound correct or is very new (for me)...

1024 faces, although for some reason Zbrush says a basic starting primitive has 1056 vertices. Math class is hard. Anyway, when you're starting out, I'd recommend playing about with a primitive that you know will work, such as a 32x33 sphere, then later on getting into such things as oblong sculpts. The 64 and 128 thing is referring to sculptmap size, which really doesn't have to be that large. You're right, a 128x128 sculptmap is usually more than large enough, and often a 64x64 is just fine. There's a bit of trial and error involved; just export as a small map first then see if that's good enough.

For someone with no 3D background, I'd recommend Natalia Zelmanov's tutorials (scroll down the page for the sculpted prim series):
http://www.mermaiddiaries.com/2006/11/build.html
They start with Rokuro, which can be learned in about 15 minutes, then finish with the basics of Wings3D (a free, but moderately powerful program) and texturing.

Those will give you a feel for things, and you can decide where you want to go from there.

In case you are interested in the math :

think of your 1024 faces placed in a square plane of 32*32 faces. This is the basic object out of which all (standard) sculpties are made. So how many points do you need then on each axis to make the object? Answer: 33.

Hence 33 on X times 33 on Y makes up 33*33 = 1089

ok. Now imagine, you bend the plane in such a way, that the left and the right side match up. You now have a cylinder. At the matching area (the seam) you have duplicated vertices. Exactly 33. remove the duplicates and you end up with:

1089-33=1056 vertices for (basic) cylinders

Thats what ZBrush refers to. Furthermore, as you already pointed out, for cylindrical and spherical sculpties you need only 32 pixels in the X dimension(hence 32*33 sphere). the missing 33 rd column is the just removed duplicated one. Hence

32*33 pixels = 1056 pixels are suficient for cylinders

Now for the sphericals: The poles are made up of the first and last row of the object by pulling all points together to one point, the pole. Now we have again 32 duplicates at the top and at the bottom. But these duplicates are NOT removed. In fact Cylinder and Sphere are more or less the same. In Sl a sphere is just "a closed cylinder"

Finally look at the torus: Take a cylinder and bend it such that its ends match up. You get a torus and another 32 duplicates at the seam (32 not 33 because we have removed the 33rd column earlier). so for torus we end up with:

1056-32=1024 vertices. (matches with 32*32 pixels)

Hence technically a torus can be transported with an image of size 32*32 and i think it is the only sculptie type which realy could be transported lossless with a 32*32 image...


I was searching a long time for an example where 128*128 shows better results compared to 64*64. Please can you provide an example where a 128*128 map gives more precise results over a 64*64 map? I am interested in examining that map and understand why that happens.

Thanks for the explanation on vertices. I actually followed it



Well, as you can no doubt tell, I'm more in the "practise" versus "theory" camp, so I all I can say is that nine times out of ten, my maps do just fine at 64x64. Every now and then I have a map that seems to work better at 128. NO idea why, although it seems to be sculpts with sections that are susceptible to loss error (projections comprised of just a few faces, narrow sections, etc). Sorry, no scientific answers, I just fiddle until it seems to work.

No problem with "practice over theory" here That was may way until i started to get some deeper understanding about what i am talking while we created the machinimatrix videos

Anyways, if you got the chance to stumble over such a problem with 64*64 images again, i would love to take a look at the sculptmap and i would like to check if this is a matter of your toolkit exporter or a principal problem with sculpties at all. All i want is to find out what's going on Are you working with zbrush ?

Zbrush, importing through Sculpty Maker for the most part. I also use Maya for some shapes, but haven't had any problems with that. When I model in NURBs, what I see is very much what I get.