convert to volume feedback

[calibrix]

I'm trying to understand how the convert to volume is intended to function. It handles SDF and fog volume conversion nicely, but it has some unexpected quirks when converting other properties. If I make a property called "point_testVal" and this point property varies from point to point. I would expect to when the points are voxelized that I would only see their values stamped at the point positions at a given point_size. But instead I see that the values are spread throughout the voxel_tile tree. What I mean is that if I have points that have values between 0-1. I would only expect to see values greater than zero in the area near the points and all other parts of the voxel_tile_tree should have values of zero. That's at least what I would intuit from using the convert_to_volume node. Instead, what I get is any value that a point has gets mapped into the voxel_tile_tree almost like it's raycast off in to infinity. This makes creating custom volumes difficult as I then have to store a 0-1 fog_density where the points are (which works as expected) and as a second step multiply that against my other voxel data to cull them. I would like to suggest that the convert_volume node should only stamp data where the user specifies and all other voxels outside the range of the converted geo should remain at a background value. Note that in my example scene I'm using a level set, but the same thing happens with a fog volume. See my attached screen shot and example file for further details.

Something further I'd like to add, the convert to volume can create both level sets and fog volumes, but don't explain to the user what those are, why they are different and when to use which type. I have a pretty good handle on what those mean in the context of VDB or Houdini volumes, but I'm not 100% positive those terms are the same in BiFrost. There doesn't appear to be any documentation explaining their functions in detail. Perhaps it would be good to add a "working with volumes" section in the bifrost documentation to help new users understand how to use the volume nodes.

[stamatk]

Hi @calibrix 

Thank you very much for taking the time to provide this feedback, as it is extremely useful to know what your experience is with converting to volumes, what you're expecting and what it's actually doing currently.

Bifrost's volume conversion process and workflows are ever evolving, and we're currently working to define what the next batch of work looks like. There is definitely still a lot to do with respect to performance, usability and intuitiveness, but also with more technical aspects like what's happening with the data, where and why. So rest assured that your feedback here will be taken into consideration as we sort all this out!

Thanks again,
Kosta