Massive VDB instancing

[martinscube]

Is there planned some improved instancing of the VDB volumes?
I'm working on some cloud heavy scenes, everything is great, but when I try to make around +1000 copys of VDB obejcts using Cloner (with OctaneScatter it doesnt work) the scene loading time can take almost 10minutes.
Good thing is, it doesnt use much GPU ram.

Also when there is heavy VDB volume overlaping, the bounding box of VDB creates cutout in other volumes ( I will post example later)

Here is a simple example of what i'm doing, i just need to make them much moooooore

[aoktar]

Clouds look great. As i know octane use some optimisations when you use same vdb files.

[haze]

Is there planned some improved instancing of the VDB volumes?
I'm working on some cloud heavy scenes, everything is great, but when I try to make around +1000 copys of VDB obejcts using Cloner (with OctaneScatter it doesnt work) the scene loading time can take almost 10minutes.
Good thing is, it doesnt use much GPU ram.

Also there when there is heavy VDB volume overlaping, the bounding box of VDB creates cutout in other volumes ( I will post example later)

Here is a simple example of what i'm doing, i just need to make them much moooooore :)

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In this case what is likely causing the scene load is the BVH construction, probably made worse by overlapping. When instancing volumes in Octane, the volume data will never be duplicated.

The cutouts you mentioned are a limitation of volume rendering. The ray marcher has to choose a step length, and when it is too large for the interval to be integrated, it will make one huge step from start to end of the interval. In the case where volumes overlap, the overlapping interval can sometimes be a lot shorter than the portions that don't overlap. In other words, if the volume is physically very dense, lower step lengths will make it appear to be less dense, but as soon as the volumes overlap, then the overlapping portions will actually be more accurate. A similar effect will happen when using two volumes with very different step lengths, and overlapping them.

I suggest that in workflow, first ensure that the volume is accurate, by finding a balance between density and step length, ensuring the step length is as low as possible without killing performance. Try to minimise overlapping, this will improve ray marching performance.

[martinscube]

Test I created was done using the same VDB volume that was made as instance, and that instance was put in the cloner.

So the best way to avoid visible boundin boxes is to keep step lenghts same as possible and do little or no overlapping?

[haze]

Test I created was done using the same VDB volume that was made as instance, and that instance was put in the cloner.

So the best way to avoid visible boundin boxes is to keep step lenghts same as possible and do little or no overlapping?

If you do need to overlap, then try to keep the step lengths as low as possible - doing less overlapping will make it render faster.

[Chriz]

Hi,

i mentioned the same problem yesterday in an other post.

I am working on a cloudsurface with many cloned VDB-clouds too. Steping into the same problem with the boxes.

Using a low step length is helpful, but the clouds are very dens than. And that is kind of opposite what i try to achieve... using same length for intersecting VDB may work sometimes, but it did not help in my case.

I would like to know, if we can hope this will be fixed someday, or is this an absolute limitation with the volumes in Octane?

Best, Chriz

[haze]

Lowering the step length makes the rendering of your volume more accurate - if the volume appears more dense when lowering the step length, then you will need to lower the actual Density of the volume too. We experimented with several other sampling techniques, but settled on the uniform step length because it allows our customers more control over accuracy vs performance.

The ray marcher will miss a lot of information about the volume if the step length is too large, especially when there are dense parts to the volume.

If lowering the step length did not help in your case, then please send us an ORBX so that we can take a look into the issue.