CGTalk - Trouble with rigid bodies and shatter

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Tolerate

08-08-2002, 10:09 PM

I'm hoping someone knows why this is happening and how I can fix it

I'm crashing a spaceship into the ground and wanting it to break up pod race style-ish, everything looks pretty much how i want it.

I'm using the technique from the online manuals to shatter it on impact and it worked fine on a test but when I use the final landscape object and keyframe the shatter on, everything messes up

The ship moves faster than before I keyframes the shatter property

This leads the ship to hit the ground at a different time and position than when I set the keyframe, which obviously ruins the entire effect

I've put a link to 2 playblasts I did to show exactly what I mean

Proper Crash (http://www.btinternet.com/~scorpy/Crash.avi)

That is the one which is behaving properly (apart from it bounces too high, but that is easily corrected). I am simply wanting the ship to hit the same point at the same time after I turn the shatter property on in the channel box.

But instead this is what happens:

Messed Up Crash (http://www.btinternet.com/~scorpy/Crash_Bad.avi)

If anyone is willing to help, the technique I am following is in the online help under dynamics

bigfatMELon

08-09-2002, 06:14 AM

Aside from speed, they both appear to be hitting the ground and bouncing off of it as a single object. I guess there is some shatter going on in there but it's not really noticable.

I would suggest changing the keyframes to achieve the original speed. The Shatter effect would not be responsible for changing the speed of the craft. You must have inadverntently changed the timing.

Also, you need more gravity in there. :)

-jl

Tolerate

08-09-2002, 08:17 AM

Well, the *only* thing that I changed is to keyframe the shatter effect on

I haven't even touched the timing

wireFrame

08-09-2002, 09:42 AM

I havem't done want you wanted to do but my approach would be like this.

I'll construct that craft in a way that I it's composed of different parts; the way Habib Z. did it on Anakin's pod. Constraints and dynamic will play a major part in the crash. It's keyframeable (on/off) and I think it will make it more realistic than shattering that geometry which is messing up your animation.

I'll assemble those parts the way it should look and fly and when it hits the ground, I'll sequencially disconnect by keyframe those constraints that attach the parts to the main body/frame and have dynamics take care of the scattering animation.

By the way, that craft when it hits the ground shouldn't bounce like in your first animation.

I'm sorry that I can't answer that shatter problem of your and all I can do is suggest.

robertp

08-30-2002, 12:58 AM

Hi you need to up your mass of your object. It looks like a bouncy ball. How big is the ship suppose to be? Plus add some friction to the groundplane. its under the ridge body node attacted to the ground plane.

Rob

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