Hi Marco,
An explosion is the bread and butter of an FX TD.
Simple break down for the FX:
1) Need a high resolution model that is about to get blown to bits. Model time
2) Separated version of the high resolution model - i.e. pieces, from large to small - Model Time
3) Low resolutions versions of #2 -
4) Turn the Low resolution pieces into Rigid Body (RBD) Objects with a force at the point where the explosion occurs
4a) after a LoRes simulation of the RBD is done, you bake out the channels and copy them to the high resolution pieces from #2
5) particles - instances using #2 - large/medium size
6) Another particle system for grit (very small points or small instances)
7) Yet another particle system for Dust
Now timing...
You need a HUGE force at the point of explosion.
WATCH references of real explosions to see how FAST they occur, then slow down.
Take your small particle system (as it is the easiest and fastest to work with) and put a volume axis field at the point of the explosion and make sure attenuation is left on. (you might need a drag force as well and gravity force)
The force should be in the 100-1000.... the particles should go from the center and travel about 80% of the size of the explosion in about 4 frames! Again look at reference footage - it is very FAST for the first few frames - give or take a few frames.... then the dust hangs around.
Once you are happy with the speed and size of the explosion, transfer these forces to the RBD simulation, the instance simulation and the dust system.
Creating a good explosion takes good timing and hang time.
Have fun
C
