So, I've gone through the fluids tutorial vids … still have a few questions about the rendering of volumes.
Generally, I see a few of the component pieces to render volumes, but does anyone have a good workflow for rendering smoke/puffs etc.
It's easy enough to get the look with still geometry, but what is a good workflow with particles? Is it possible to set up anything similar to Afterburn etc?
So, should I be …
a. copying spheres onto particles and making “clouds” from that
b. using the “point cloud” feature of the Iso Offset
c. Doing the volume simulation in DOPs to generate the cool looking motion
d. something else entirely?
So, making smoke; can it be done efficiently and what's a good way to do it.
render Houdini volumetrics
3963 2 1- andrewlowell
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- johner
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If you're looking at a particle-based solution that's still volumetric (i.e. not sprite-based), you might want to spend some time dissecting the Smoke:Heavy tool that comes with the FX Tools shelf you can download from SESI, if you haven't already. Basically it copies metaballs onto particles, then renders them with the “Metaballs as Volume” (vm_metavolume) parameter set to true (under the Render/Geometry tabs).
The tricky/clever thing with this approach is that you still need some sort of noise that travels with the smoke to get convincing detail. So that's one of the reasons the tool requires you to write out the metaball geo to disk as well: the volume shader can then read the metaballs in and loop through all metaballs affecting a given point, and use each metaball's local space to generate a noise value. The result is noise that “sticks” and combines as the metaballs move around.
It's very straightforward to plug your own particle system into this setup and shader. Very quickly: add a Smoke:Heavy node, then Allow Editing of Contents. Go into the smokerender Geo Obj below that, and swap out the POP network in there (popnet1) with your own.
There's obviously tons to be done with a DOP fluids sim and stuff to get convincing smoke, but it's worth having a look at this approach if you're trying something Afterburn / particle-ish.
The tricky/clever thing with this approach is that you still need some sort of noise that travels with the smoke to get convincing detail. So that's one of the reasons the tool requires you to write out the metaball geo to disk as well: the volume shader can then read the metaballs in and loop through all metaballs affecting a given point, and use each metaball's local space to generate a noise value. The result is noise that “sticks” and combines as the metaballs move around.
It's very straightforward to plug your own particle system into this setup and shader. Very quickly: add a Smoke:Heavy node, then Allow Editing of Contents. Go into the smokerender Geo Obj below that, and swap out the POP network in there (popnet1) with your own.
There's obviously tons to be done with a DOP fluids sim and stuff to get convincing smoke, but it's worth having a look at this approach if you're trying something Afterburn / particle-ish.
- andrewlowell
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