Crumbling rock

[scribla]

Hey, I need to make cracks appear in an object, and then have the object fall apart at these cracks...something a lot like the cracks in the Ice Age preview would be really good.

I've got a monkey walking along a high mountain path, and I need the path to crumble away beneath his feet.

Thank you thank you thank you.

[joojaa]

In reply to:
Hey, I need to make cracks appear in an object, and then have the object fall apart at these cracks...something a lot like the cracks in the Ice Age preview would be really good.

Just make lots of geometry and use rigd body dynamics...

[scribla]

So how might you suggest I might show the cracks forming?

This is really the effect that I'm after at the moment...

[joojaa]

Boolean operations, just kidding? Depends on how accurate you want it to be, split polygon will give you most controll but shatter should work fine. Remember that people only look at the sequance quite briefly so you could key the breakup first a bit by manually keying(this has to be done anyway as the rigd body solver will fail if your objects are too close at the begining). I would probably render this in 2 or more passes and make the cracking partly in 2d (thisway you can fade, or switch more inteligently from solid unbroken to broken with controll, so that the separation isnt visible untill it should).

[goli]

You could also do this with animated ramps, both as texture and bump.

In reply to:
So how might you suggest I might show the cracks forming?

This is really the effect that I'm after at the moment...

[clappy]

The quickest way to animate the cracks, would be to render a frame of the geometry with no cracks. Then apply shatter to your geometry and render out a frame with the cracks. You would then need to use the alpha channel of the the image with the cracks to create an animated matte in a program like After Effects or Combustion. This might be easier to tweek and preview than doing the whole process in Maya.

Animating the ground crumbling and falling beneath the monkeys feet is probably as simple as applying some dynamics to the shattered geometry and mixing in some instanced particles.