I have an object representing a piece of pottery rising flaming and smoking from a fire pit (Smoke and Fire Simulation). I stop the fire then animate its diffuse material changing from emitting orange to dull gray representing cooling. All this takes place between frames 1 and 250. I have rendered this part and it works and looks great.
Now I want to animate the pottery falling and breaking into shards (guessing I’ll use Cell Fracture, but I’m open to ideas).
The conceptual problem I have is how to get the falling fracturing effect to begin on frame 251? Would I have to actually create a second copy of the object, make it fall and fracture, render that animation, then somehow seamlessly (difficult) splice the two animations together? Or how can I make an object all the sudden forget that it is a smoke emitter and begin acting like a fracturing object?
Yes you need to composite the render of the whole object and the group of shards into one animation in post. Animated texture should be fine. Not sure if the fracture script will copy across the smoke flow to all the shards - if so do the following:
If you want to separate all your elements, bake your smoke sim, uncheck the renderable toggle on the pottery which is the emitter, make a duplicate and remove it from the sim - this will be the solid renderable one. Fracture this and use the shards with the physics engine (this will ensure the shards aren’t all smoke emitters too). Then composite the render from 1-250 and 250-… together (or have a few more frames overlap that you can blend between). Not sure how much benefit making a separate pottery for the sim would be unless you have a low poly mesh for emitting and a duplicate high poly mesh for rendering. That’s assuming the sim takes a performance hit when calculating flow from a high poly mesh.
Thanks for taking the time! And I think I get it (!?)
The smoke and fire get baked around the original object (an emitter). Then a copy of the object is made and the original object is deleted. If it turns out the new object still has the smoke sim on it, I can remove the smoke sim data. Then do a cell fracture with it. It occurs to me I think I can use the new object all the way from frame 1 if required for some reason, since the fire sim is already baked. The object emerges from the fire knowing nothing about its part in the fire part and proceeds into its cell fracture. And I think I can handle rendering the shards with the help of the cell fracture tutorials.
Anyway, I’ll give this a try with a simpler model. Thanks again!