I'd like to use PolyVox to store all my voxels, although not every one of them has to be processed by marching cubes.

So, first question:
Is it possible to ignore certain kinds of materials during mesh generation?

And one more:
It would be useful to have possibility for:
a) registering callbacks onMaterialMeshExtract, called for every voxel with given material
b) or just listing voxels from volume *by material*

So:
a) if i missed any of these features, could you tell me about it?
b) if you think any of these features should be in polyvox, are you planning to make it?
c) otherwise, do You have any propositions or advices for me how to implement them?

Thanks

No, that's not currently possible. However, you could take the generated mesh, iterate over the triangles, and delete those which have a vertex with the material you don't want. Maybe that's good enough for you? What are you trying to achieve?




There isn't this functioanlity. I have thought in the past it might be useful to have a new surface extractor which, instead of actually generating a mesh, would just generate a list of voxels lying on the border between solid and empty space. For example, you could then take that list of voxels and render a user-supplied model at each point instead of a cube. I haven't really looked at this any further though.



I guess you can find this information yourself, just by iterating over the volume, looking at each voxel, and keeping track of what you find?

The way I do that currently is by copying the part I want to extract manually and erasing any voxels that I do not want.
I have not done any performance tests on this, but since I'm copying that part of the volume to a completely different thread for extraction anyway, this shouldn't have too much of an impact.

I'm not sure you understood what i ment. I've been talking about some kind of separate structures for by-material enlistment. Whether it would be performance worthy, I'm not sure - just a guess.

So, thank You both for answers. Looks like i'll remove materials of choice before each decimation.

My idea isn't really original in replacing some voxels with complete meshes, or put them to l-system based generator.

I'm still not quite clear what you mean here. Rather than storing all the voxels in a single volume, you'd like a structure where the different material voxels are stored seperatly? Or you mean that after running the surface extractor you would like several different meshes - one corresponding to each material?

However, as mentioned here, it will be a little while before I can give you further information.

This would be very helpful. Just had to break my silence to let you know. Also, I'll take this opportunity to thank you for PolyVox.

It should be straight forward to implement - I've added it to the short term todo list.