Hi, I’m wondering if there’s a method of automatically generating alphas/height maps geometry within Blender, similar to the MRGBZGrabber in Zbrush. Basically, I want to do something like this:
But without having to go through compositing. Is there an addon that will allow me to do this?
I’m not really familiar with the term “alphas”-- does it imply some kind of transparency in this context?
Skimming that vid, it looks like all he’s doing the compositing for is to normalize the height. For certain kinds of meshes, you can get normalized height directly in your materials, by using generated texture coordinates (but last time I looked, behavior was a bit buggy with regards to preview.) Generated texture coords create a box, from 0-1, surrounding your object, so the lowest part of your model is going to have generated.z = 0 and the highest part of your model is going to have generated z = 1.
I said “certain kinds of models” because there are caveats. IIRC, curve objects act different. Generated texture coords are generated after shapekeys but before modifiers, so modifiers can take them out of bounds. Object rotation can mean that your generated texture coords aren’t in your world axis. But all of that is rectified very easily, by applying rotation before render if necessary, and doing an alt-c curve-to-mesh (which when used on a curve or text, will turn it to mesh, and when used on a mesh, will apply all modifiers.)
There are still caveats; curve->mesh doesn’t work perfectly in all situations; parented objects may still not have proper rotation after applying rotation; probably a few other corner cases as well. But for typical use, that should do the trick.
I see, so it’s quite a bit more complex than I thought. By “alphas” I mean a greyscale map that could be used as a brush texture for sculpting, and Zbrush has a feature that allows you to select a mesh and automatically create one from it.
Most of the time, you don’t have to worry about anything. Just sculpt something, emit generated.z in mat, render to ortho camera. I wanted to warn about some of the issues that could come up.