VDB workflow testing

Started by Matt, June 13, 2018, 07:18:11 am

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Oshyan

No update on the Windows version. When it is available we will definitely let everyone know.

- Oshyan

D.A. Bentley

I found this today (It could be useful for testing / research):
https://www.technology.disneyanimation.com/clouds

Oshyan

Yes, when we get to VDB import we'll almost certainly test that data. Very curious to see how that cloud renders in Terragen. :D

- Oshyan

D.A. Bentley

Hi Oshyan / Matt,

I wanted to get some more clarification on what settings affect VDB Exports. 

I know most of the settings are on the Optimisation / Optimization tab of the cloud, but the size of the cloud affect the voxel buffer size too (Cloud depth, Radius).
Are there any other settings that can alter the voxel buffer size?

What about the "Accelerate empty space"?

What about "Transition dist. (voxels)" which has a default value of "8"?

Thanks,

-Derek


Oshyan

Matt is away for the weekend, but I'll do my best to answer, within what I know, and he can clarify/correct when he gets back.

The size or depth of the cloud doesn't generally change the number of voxels, which is what I would call the "voxel buffer size" (the "size" being the size of the buffer as a whole, rather than individual voxels). It does change how they're distributed, i.e. what size each voxel is (how much area each voxel covers), so perhaps that's what you mean. If you want to maintain detail while increasing cloud depth or area of coverage, you need to increase voxel count. You can see these values for x, y, z voxel distribution updated beneath the voxel count slider, and it is affected by cloud depth, etc.

Transition Distance only applies to using voxels for shadows, which doesn't affect VDB export as far as I'm aware.

I'm not sure about Accelerate Empty Space, but I would guess it has no effect for VDB export. My understanding is this just limits cloud visibility calculations to the voxel area, but the VDB export *only* exports the voxels, so on or off shouldn't make a difference as far as I can imagine. But I've been wrong before. ;)

- Oshyan

D.A. Bentley

Thanks Oshyan!

One other thing I wanted to ask is if it is possible to make -exportvdb work with the -f frame ranges like it does with rendering images?

I have been animating certain cloud settings to get different cloud shapes (mainly the seed value) so for example I set my frame range in Terragen from 1-256, and animate the seed with a linear curve from 1-256 as well, so at frame 79 I am going to be exporting the cloud with seed 79.

Currently I have been making a batch file / shell script (.sh) with each line in the .sh file specifying the .tgd file and commands to export one .vdb file.
In doing this I have to manually save out each .tgd at the frame I want exported.  When exporting hundreds of little vdb clouds this takes awhile.

So it would be nice if I could just do something like this instead:
./terragen -p project.tgd -exportvdb "Easy Cloud 01" output.vdb -f 1-56, 61,62,89, 111-189, 253,255

That way I could do everything I have been doing but just working with one .tgd file.

Lastly, if this is possible and I isn't too much to ask would it also be possible to add a voxel override switch to specify the millions of voxels to use?
./terragen -p project.tgd -exportvdb "Easy Cloud 01" output.vdb -voxels 800 -threads 8 -frames 1-100, 256

Just some ideas.  :)  I have found using Notepad++ can help me with some of this when having to work with hundreds of separate .tgd files, but it sure would be handy to have these two additional command line switches.

Thanks,

-Derek

paq

February 23, 2019, 11:33:39 am #81 Last Edit: February 23, 2019, 11:37:01 am by paq
Hehe Matt is aware for this 2 requests  8)

For the second question I copy/paste his reply (hope he doesn't mind)

You can set the frame in the command line using the -f argument, in the same way you would if you're rendering a frame. That will get you a different point in the animation. However, the cloud filename doesn't know about file sequences, so you'll need to declare the number in the filename. If you're able to script something, you could write a loop to generate the filenames and execute Terragen with the -f argument. However, I don't know how stable the output will be in a sequence.

Didn't had the time yet to try that script suggestion.
Gameloft