Smoke Simulation / VDB support: How does it work?

[regionfive]

Finally V3, feels like Christmas

Does the smoke sim work yet in V3? The switch between Point Cache and VDB is greyed.

How do I setup a smoke shader in the Blender node tree?

Thank you!

[pegot]

I believe you first have to save the blend file before you can switch cache settings to VDB.

A detailed smoke tutorial BTW would be greatly appreciated.

[regionfive]

nooo way that really was the issue, didn´t think about it... got it working, thanks!

I could consider doing a smoke sim tutorial. I have made https://vimeo.com/156404455 this here earlier this year, when GPU smoke still wasn´t implemented in cycles. The color smoke of the beginning was entirely done in Blender. But rendered on a farm because of the heavy cpu times....
Now I have a similar project I need to finish until the end of September.

If I don´t have another project coming up, I could invest some time to do a Blender / Octane Smoke tutorial. Who else might be interested?

[grimm]

I have been playing around with it for a couple of days and have gotten pretty far with it. Just a caveat here, I don't know if this is the best way or the only way.

I have been hooking up the volume medium node to the smoke domain output node. I leave the smoke flow object unconnected to anything. Then there are additional settings for when the plugin loads the OpenVDB cache in the smoke domain "object data" properties panel. This panel lets you set the multipliers for the OpenVDB data. Between the two I have been able to get ok looking smoke, but I haven't yet figured out how to color the smoke.

I think a tutorial would be great!

[grimm]

Here is what I have so far, just a quick test with a simple scene.

stats:

scale: 100
step len: 0.5
absorption: 0.3
scattering: 0.3

volume properties from the object data tab:

iso: 1
absorption scale: 500
scatter scale: 500

I should add that I let it render to 500 samp/px.

[Seekerfinder]

Here is what I have so far, just a quick test with a simple scene.

Wow...

[pegot]

Nice!

[regionfive]

Hi grimm,

Coloring the smoke is easy: Just plug a RGBSpectrum Texture Node into the Absorbtion input of the Volume Medium.
The color you absorb leaves the rest of the color in the smoke. Meaning if you absorb cyan, you´ll get red smoke.

Good tip with the Properties Panel

Best,
R

[pegot]

This is just an FYI in case some beta testers of Mac Octane Blender have issues seeing the smoke preview in their viewport. That's not a problem with the plugin but it is a known Blender issue that seems to affect some Macs.

I filed a bug report on that some months back and it is being addressed by the developers:

https://developer.blender.org/T47991

[grimm]

Hi grimm,

Coloring the smoke is easy: Just plug a RGBSpectrum Texture Node into the Absorbtion input of the Volume Medium.
The color you absorb leaves the rest of the color in the smoke. Meaning if you absorb cyan, you´ll get red smoke.

Good tip with the Properties Panel

Best,
R

Thanks, I did try that but the absorption input pin would not accept the RGBSpectrum node's output. That was with 10.2, I will test tonight on 10.4 and see if it is working now.