[kami]

Hello
Is there any way to improve voxelisation speed? Or putting the question differently: what makes voxelisation slow? Is it only geometry or are textures important too?
I noticed that some parts of the voxelisation and the 'preprocessing data' only runs on one core. So for animations it would be wiser to use many slower machines than a few very powerful dual Xeon machines ...
We've run into an issue with one animation where actually the render time is not a problem, but the voxelisation time takes longer than the render itself. Any idea on how to fix that other than simplifying the geometry?
Cheers

[nachob]

Hi,

Voxelization is only geometrically related, textures are not important except if they affect geometry ( displacement ). Procedural geometry is slower to voxelize, and also having Motion blur when not needed can increase voxelization time.

If voxelization takes more time than render, or the render is very fast or maybe that scene is finding some extremely slow path in the voxelization, if you could send us a scene where that happens we would be really interested in checking whats happening under the hoods and try to improve it for the future.

nachob

[seghier]

why we can not save voxelization ?
when i stop render and open the mxi again i will wait long time for new voxelization

[choo-chee]

why bother? typically voxelisation takes less than a minute. sometimes it will take 5. but the render takes a day or two....

[seghier]

why bother? typically voxelisation takes less than a minute. sometimes it will take 5. but the render takes a day or two....

not always
sometimes take long time
and when you close and resume render voxelisation calculated again and take long time again

[kami]

hey nachob
I think my scene is not very unusual. It just has a lot of trees and other geometry in it. So it might be pretty normal that voxelisation takes a few minutes.
For an animation, that can mean that the render times per frame (if it is not full HD and only a preview SL of can be shorter than the voxelisation time, and sadly it does not make sense anymore to use the progressive render mode for these kind of scenes.
Of course it would always be good if the voxelisation process can be improved under the hood
But I think in my case it is the amount of trees and buildings that we need. Do you want me to send you the scene either way?
cheers
kami

[nachob]

why we can not save voxelization ?
when i stop render and open the mxi again i will wait long time for new voxelization

The problem is that voxelization usually takes a lot of space (usually more the more times it takes to calculate) and keeping it in the file would make it grow even more that it already needs. And if you change something it would need to be recalculated the whole thing. Fire doesn't need revoxelization of all the scene between changes because it uses another voxelization scheme, that allows fast updates but is also a bit slower when rendering, and we don't want that for the production engine.

nachob

[nachob]

But I think in my case it is the amount of trees and buildings that we need. Do you want me to send you the scene either way?
cheers
kami

As you wish, if you send it to us we will check, evaluate performance with it and will try to get some improvement. But as you said it may be not possible if it is just standard geometry, but will give us a target scene to work with.

nachob