this is a brief tutorial about re-topologising in blender...
it's not step by step, but might be of use.... I'll expand depending on peoples needs...
1: First export your model as an obj from sculptris
2: import obj into blender 2.5.
2.5 these days should work by default for both, but 2.49 will require non default import options: NB the defaults are fine UNLESS you have mapping data from paint mode... if you do you MUST enable objects and groups...
3: add another object that will be the basis for our new topology (a plane will be fine)
4: with that object selected enter edit mode (via the 3d view header or hit "tab")
5: enable snapping, face mode and projecting onto the background geometry in the 3d view header bar:
in the above illustration you can see the finished "cage object"
This was built by selecting edges of the original plane object and extruding them over the surface of the model... the "snap" mode conforms those edges to the background model.
that was pretty much it barring some pulling vertices around and making some faces by selecting two edges and hitting "f"
that's all really!
you'll need to know what constitutes "good" animation geometry, edge loop theory etc etc...
Whilst doing the above it's a good idea to be able to check how well the cage will work subdivided, also if the model is symmetrical a "mirror modifier" will help.
6: in the "properties" region go to the "modifier" tab.... add a "multires" modifier ("a subsurf" modifier will work too, but multires will allow further sculpting in blender's own "sculpt mode"). Enable "optimal draw" and subdivide a few times... You'll probably want to use the "preview" slider a lot to toggle up and down subdivision levels in object mode as you go.
7: if the model is symmetrical add a "mirror" modifier.... the "clip" button makes the mirror plane sticky and stops penetrating the other side
8: to make the generated subdivisions "stick" to the underlying geometry add a "shrinkwrap" modifier... The target should be the obj object that you imported..... change the mode from "nearest surface point" to "project" and "enable" direction to negative and positive....
the right hand column shows the base cage and all the modifiers....
now, you can "tab" back and forth from edit mode to object mode and see exactly how good your retopo is!
subdivided once with multires....
subdivided twice... note how the generated loops fit to teh target mesh with shrinkwrap
keep going until all the detail from your sculptris mesh is "captured"
you may want to go the " object" tab and enable "wire" to draw over your cage model... if you've selected "optimal display" in your "multires modifier" you should get a clear view of the edge loops and whether they follow your topology nicely or not
finally, when happy, you *should* be able to "apply" the shrinkwrap modifier to your object and turn off all teh snapping... from here on it's as if you sculpted it natively in blender and you can subdivide it some more, detail up with blender sculpt whatever....
... or just add an armature and rig it up to animate!
I know this probably requires a lot of advanced knowledge of blender and what good topology is, but maybe it helps! let me know and I'll endeavor to improve this tutorial!
I can do a follow up for transferring mapping and sculptris bump and colour maps to the new model too if anyone's interested.
I must be an idiot, because this tutorial makes no sense to me and isn't working, when I try to follow it. Could you make a more comprehensive tutorial on what to do with it?