What would be the best way of simulating a guy landing on a pavement slab (after just jumping) and producing a smallish crater where he lands and cracks eminating from that. I thought about DOP's and RBD's but isn't that more for stuff you want to specifically break apart not for simply fracturing/cracking an object?

Thanks for any suggestions…

I would go down the displacement road.
Mix of deforming geometry and animated diplacement + little bit of particle debris.
I did the displacement part for one project. I animated the crack on the ground, and it worked quite nice.

Thanks, that sounds like a good solution. For creating the cracks I would use a negative displacement map you mean? I.e. set the displace amount to be a minus value so it intrudes into the geometry? What would be the easiest way of producing an animated displacement map? I would like a fractal-like pattern, so I assume I'd have to create the pattern and make it ‘grow’ accordingly?

Depending on what you want to achieve, you may just be able to get away with building a before and after model, and swapping in the new one when the guy hits the ground. That's certainly what I would try first, because I'm old and lazy.

yeah, your way is easier for sure. I am just one displacement fan, so whenever is possible I try to displace things.
The way I did the “crack thing”:
I needed clean “ice age” like cracks so I did a 2d animation of a growing crack with pen and paper and then trace it in shake to make blac&white map. In one word I drew every single crack from beggining . I rendered everything in renderman, so I think mantra will handle things nice since it's also micropolygonal renderer.
But, in the end I am not an expert, and there must be more elegant ways to do this…

djorzgul_strashni
so I did a 2d animation of a growing crack with pen and paper and then trace it in shake to make blac&white map.

You might want to check out the Trace SOP next time.

What would I use the trace SOP for? I've been working on it today and I've drawn a crack pattern in Photoshop and taken it into COP's. I've then keyframed the size property on a dilateerode node over four frames and used that as a negative displacement map. Was also thinking I could keyframe the magnitude of the displacement as the cracking progresses? Any other suggestions would be welcome!

Sorry, I didn't read your original post properly. The Trace SOP would be useful if you wanted to generate geometry from your images.

hehe
thats why I started to learn houdini…

You could draw white cracks on a black texture and then overlay (multiply) a white to black radial gradient over it to make it fade from full brightness in the center of the texture to black at the edges. Then drag a brightness threshold over it from light to dark, and it will look like the cracks are spreading out. A little refining and it should look pretty good.

See the image bellow for a simple example…


Take care, and good luck!

brilliant !!!

great tip.
and there is cool topic on the odForce on this matter, in case someone missed it:
http://odforce.net/forum/index.php?showtopic=4032 [odforce.net]

Thanks for all your help guys….