Hi !
I would like to share some results and get some advice.
I made an explosion i would like to render with Octane. Simulation is like i'm expecting to be, no trouble with Octane neither, everything works fine. Interaction of the smoke with lights is pretty neat and fire is lighting up my smoke.
I checked Casey Hupkey NAB 2016 presentation to match his settings and found out he was true : Volume Step length for fire and smoke settings is around 0.2. So far, i'm getting good results.
But i can't get very much detail in the smoke. No matter what i do, i still get some big round results around the edges and most of the small details are gone in semi-transparent smoke.
When i try some test files shared in the forum, i can notice the same kind of results. Small details are gone and i would like to know if there is a way to get them back.
So far, i'm rendering some extra pass with Atmosphere pass in Standard Renderer and composite it in post.
Here is a picture of the simulation.
There is a lot of detail in it, this is an 2x upres simulation.
My settings are OK. Volume Step Length is at 0.3 and Density at 2000 to get volume density as i would like to be.
I found out there is no much difference if i lower density and lower Volume step length. Render time increase but i don't get much more detail.
I made a custom emission ramp to have more detail in the fire colors. Came out pretty good. I animated Max value to prevent overexposure at the beginning.
Here is a picture of the result i get from Octane Live Viewer. Render time is around 5 to 7 minutes with GTX 970 (1000 max samples)
Even if i increase max samples, grain go away but my detail problem remains.
And here is the result i get from Standard Renderer.
I placed lights to mimic the light of the Octane scene (i used a mix of HDRI Octane Sky and Octane lights). Obviously i was expecting a render difference, but my point is to show detail difference in the smoke.
Render time increase with time from 1 minute/image up to 15 minutes/image when there are a lot of details and transparent smoke
Is there something i can do to get more detail in the smoke ?
Thanks for your advice !