Can fire live forever without dissipating?

[lukepenry]

I am basically trying to create the image of the blue fire. but i can't figure out a way to remove the hot central point of the fire like in the first image. what would be ideal is to spawn some fire and have it live forever and use turbulence to move it around. is there a way to spawn fire over a few frames and have it live forever without dissipating? so far it always seems to vanish after a while.

Thanks!

[Joelaff]

You could sim to a frame you are happy with and then use animated displacement on that frame. Load a single frame from the cache.

I think the displacement is faster if you load the frame into a VRayVolumeGrid, but don’t quote me on that.

For the dark center you might be able to use a VrayDistanceTex with a sphere in the middle to modulate the opacity of the flame.

Alternately, set up the look you want (likes fireworks type thing) with pFlow or TyFlow, and then use the particles to generate fire with volume brush or possibly inject. This way you can define the base shape without slower PHX sims.

[Joelaff]

Also, it’s almost looks like you could take that sim you did and duplicate the whole simulator multiple times, translate, rotate, and scale the copies in 3d space to create a collection like your sample and color them differently.

If you use multiple simulator grids or VolumeGrids grab one of the latest nightly builds. A lot of work was recently done to improve the speed of multiple volumes. It is much faster in the nightly builds.

[lukepenry]

Thanks i'll give that a go!

[georgi.zhekov]

For the shading part, take a look at this video here - https://youtu.be/g9IcZ6udHvw

[georgi.zhekov]

I think the displacement is faster if you load the frame into a VRayVolumeGrid, but don’t quote me on that.

I literally quoted you

There should be no difference whether using VRayVolumeGrid or Phoenix. The speed should be more or less the same.

[Joelaff]

I literally quoted you

There should be no difference whether using VRayVolumeGrid or Phoenix. The speed should be more or less the same.

Well, there you go!

I guess the difference I was seeing must have been due to other settings, resolution, render settings, etc. I knew I definitely didn’t do a scientific controlled test.

One thing that is faster is the delay when selecting a VolumeGrid in Max. (When you are displaying the controls in the command panel) I think this has to do with all the rollout controls in the simulator, no? (I swear the code to draw rollouts in Max must be O(n!), lol)

However, then you have to decide if it is faster to switch back and forth. A lot of times we will use a simple scene to run the simulators and then load the aur file into the VolumeGrid in the scene to be rendered.

[Svetlin.Nikolov]

Yesss, preparing the rollouts takes awfully long and there is no specific rollout or control that takes the longest, it's just evenly distributed between all rollouts... One thing that is different between the volume grid and phx is that the probabilistic volumetrics are on by default for the volume grid's atmosphere and off for phx. We have to write some more rendering code before this can be on for Phoenix as well...

[Joelaff]

At least you can turn on the probabilistic shading for PHX too, which is very helpful for smoke/clouds.

I assume there is no way for a developer like you guys to speed up the rollout slowdowns? It has to be done on Autodesk's end? No way to cache it or instantiate objects only once or anything? It really drives me nuts all the time.

[Svetlin.Nikolov]

I hope there would be one and I hope we're missing something because in this case we can do something about it, unlike the other alternative...

[Joelaff]

Forest Pack is also very slow because it has a lot of controls.

Maybe just a floating window with Max script. That would probably be very fast (well, nothing in Max runs fast, but it would likely be reasonable). We added some more settings to the script that I think Nick posted in the best practices for clouds thread. I need to share the updates. It was much faster to make changes through the floating window than to show the command panel.

[Svetlin.Nikolov]

Yess, this is something I'm imagining as well, but additionally complicated because I hope we could combine it with some other concepts as well... making it Not Happen in the nightlies quickly... yet