width / height / depth for vray volume grid with no cache loaded! (for cheap env fog)

[joconnell]

Hi folks!

We're using the empty vray volume grid trick to get faster fog passes in here and it's fantastic for very fast preview passes. For higher quality results though it doesn't hold up when non uniform scaled and you can see the voxels when it's used in wide views. For the sake of trivia, what are the voxel dimensions of a vray volume grid object when there's no cache loaded in (as in you make the object and then hit cancel on the cache loading dialog that appears)?

Do you think it'd be possible to have a height, width and depth option on the object or some kind of "initialize" options to do this? We've got the fallback option of saving out a load of default phoenix caches in various sizes of boxes but it'd be a very handy one to have in the object, especially if you've got something you like working but need a bit more quality around a light source for example!

[squintnic]

Just tried this works well!
Agree it is somewhat annoying not to have a bounding box for selection and voxel control also having trouble cleaning up close to lights.

[squintnic]

have been using this in scene set up but then when i rendered a test animation im getting some horrible flickering using a the method above and a single disc light with 0.5 directional enabled

(the clumpy slow foam is for another thread...)

https://www.dropbox.com/s/dn30gayf2e...icker.mp4?dl=0

turning off light cache in volumetric seems to clean it up for stills but it gets exponentially slower
edit - even with light cache in volumetric turned off im still getting gentle flickering

was using these settings attached.

[joconnell]

That's a great looking sim!

We've similar in here, there's a shot of an old tree with bare branches and god rays shooting through it - the branches blocking each other make for fairly complex shadow casting and we get the same breakup and flickering except smaller, it kind of looks like bad video compression. More testing to be done!

[matanov]

Hi folks!

We're using the empty vray volume grid trick to get faster fog passes in here and it's fantastic for very fast preview passes. For higher quality results though it doesn't hold up when non uniform scaled and you can see the voxels when it's used in wide views. For the sake of trivia, what are the voxel dimensions of a vray volume grid object when there's no cache loaded in (as in you make the object and then hit cancel on the cache loading dialog that appears)?

Do you think it'd be possible to have a height, width and depth option on the object or some kind of "initialize" options to do this? We've got the fallback option of saving out a load of default phoenix caches in various sizes of boxes but it'd be a very handy one to have in the object, especially if you've got something you like working but need a bit more quality around a light source for example!

So here is a funny thing - a few days ago I went to the Phoenix guys and said "do you know what will be great ? Size controls for the empty volumegrid object."

With a lightning fast reaction from them, it was ready the next day. Stay tuned for version updates - it will be included in the next one

[joconnell]

I take it that's 4.x only?

* stares at the accounting department *

[matanov]

I take it that's 4.x only?

* stares at the accounting department *

Yep. And it's a very convenient way of making custom textured fogs on V-Ray GPU.

[joconnell]

Thanks for that Peter, adding it to the list of reasons why we should upgrade to 4.x

[squintnic]

turning off LC for phoenix fixed my issues with this. still pretty fast as well, i juts got used to the insane LC speed boost on stills!