Hi.

Can houdini be used for polygon reduction or decimation? For instance, say if you wanted to make a mesh be back in a parametric state. Reduce its polygons as if it weren't made editable (but it is still). How could this be done?

Thoughts?

remesh and polyreduce sops do that.

Remesh and Polyreduce won't result in a parametric geometry (as NURBS surfaces) - they output polygon geometry.

This may be possible with T-Splines (so I've heard people say anyway, I've never looked at them myself). Autodesk Fusion and Rhino (with a plugin) are the only applications I know of that support them. AFAIK they're patented by Autodesk… acquired by, not invented by of course.

Alternatively ZBrush's remesh tools are excellent. Still poly data, but much cleaner and more suitable for resurfacing by hand if you're starting with high res geo.

3D Coat has a decent remesher now as well, similar to the ZBrush tool.

I don't think there's ever going to be a remesher that gives you much for free. It's a bit like wondering how to increase the resolution of a photograph. You can apply all the filters you want, you may end up with a tidier result, but you're never going to end up with *more* information than you started with.

No remesher is going to give you UVs/parameterisation if you didn't start with any… the most it'll manage it to preserve it if you had it to begin with. If it appears to, then it's running some sort of auto-UV-unwrap or pelting after the remeshing, which you could just as easily queue up in Houdini… with all the caveats and limitations that auto-UVing/pelting carry.

Be that as it may, I'm very impressed with Z-Brush's latest Z-Remesher tools - it's tendency towards resolving to quads, a target polycount, the ability to paint levels of detail, and using optional curves to suggest parametrization flow make it a very handy tool.

Zremesher does not always create closed edge loops, it will frequently create spirals. That can be a problem for some types of models.