The purpose of this fire method is more of a companion effect in case a particular scene calls for so much fire that the volumetrics / simluation becomes route impractical to use on ‘absolutely‘ every part of the scene. The goal is to use volumetrics and simulation for the bulk of the fire where appropriate.
I was going to call this post ‘Flaming monkey mullets Batman!” seeing as most of my tests were setting the top of a Suzanne head on fire, (eg the first of these two videos ) but never got around to compositing the head back in.
Without further babbling on:
The .blend file contains one sphere with a standard material and one with the fire material on it and 3 modifiers. To transfer the fire effect to your own meshes you need to:
- Make a duplicate of the object you want to set on fire.
- Copy the material and the three (one subsurf, two displacement) modifiers to that fire mesh.
- Create an image (greyscale image texture recommended) that will act as an emitter mask for what is on fire and what isn’t and assign that to the texture called “Fire Mask”
- Hit render. 🙂
The idea behind this fire setup is that a previous version of the script included an entire city being burnt by dragon fire. Which sounds cool as a shot, but when you are the effects dude working in full 4k, that is a lot of fire.
Clearly some R&D needed to be done.
I don’t start in Amsterdam until December, but with fire being such a key thing I wanted to have some tricks up my sleeve before I got there. So I took the flames I had been working on before in a previous project and set about making the whole thing more convincing and more flexible to transfer on many different meshes. I’d still like to do more with it, (stuff like this can always be tweaked that little bit further…) but for now I think I’ll give it a rest until I have a set list of what fire effects I need for Durian.
“What about volumetric fire?” you ask…
Very good question. It will be more flexible in what it can do and has the potential to be more realistic. However, if a scene like the ‘town on fire’ one was to be done entirely with volumetric fire – imagine setting up the simulations needed to set the 200 buildings on fire, the trees, wooden carts, etc. In 4K. The sheer logistics of file size for the cache would be a nightmare, let alone the time to set it all up and then let it simulate. The idea is to use volumetrics for ‘hero’ fire like the fire from the dragon’s breath, fire in the foreground and so on. This fire material setup is intended for anything in the midground and background. But being 4k (yes I keep coming back to that) a midground element can still be larger than a full screen PAL render so it needs to look good.
While it is very quick to put the material on and get going, a particle system to set some nice embers flying around and some smoke composited over the top if needed will add a lot to the effect. This is intended as the base of the effect.
- Quick setup time
- Low file size
- No simulation / raytracing required at all, so it renders fast
- Can be applied to any mesh
- Empties no longer required from previous fire method I was using
- Fire ‘peaks’ are stationary and rotate with the object instead of being heavily influenced by the global coordinates. (This is something I’ll need to look at per effect shot. Might be able to get away with this limitation or might be able to fix it in 2.5 by adding a mapping setting or two.)
- Fire ‘licks’ off the top of the flame probably need some more attention
- Still not suitable for multi-directional fire like flame throwers or dragon breath. Again, we have volumetrics though so that isn’t so much of an issue.
Finally (long post, I know) there is a Blenderartists.org thread that chronicles the development of this material / effect and that is where I will be posting any further updates and tweaks. (Major stuff I’ll post here too of course.) If you use this material to do something groovy, post a render there – I would love to see it!