Hi! I have attached a scene with my problem. I have a wall that I crash a ball into. Just before the ball hits the wall, the wall starts to react. It moves up slightly and then splits into different part (just as is should). It’s like negative gravity effect the wall somehow. I would love if it was down instead of up :)

I seems to be a parameter that have to be adjust, but I can’t figure out where.

Regards / Jimmy

	Attachment
16568_i41UqWhLOYGJIcpZ6Hir.zip

It worked for me when I decreased the Collision Tolerance (Utilities>Reactor>Havok 1 World Rollout) to about 0.02m, and I also set Box01_Part_07 to be a Keystone piece in the Fracture instead of a normal piece.

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC

Set the wall objects to Inactive, and read this
http://area.autodesk.com/for...ve-when-animation-starts/

Thanks for your tips! I followed both leads but I still get a tiny, tiny upward movement. MK-3D, I got a tighter hit with CT set to 0,02m and that keystone piece made it look more natural though.
Samab, I looked at the example in your link (at the bottom) and that too had the movement upwards. I could not see any difference setting the wall to inactive. Is there more parameters that I could play with to minimize the movement? Maybe it ain’t possible to nail that wall to the ground in reactor?

I have attached a new scene.

Regards / Jimmy

	Attachment
16609_Y29BAkUTwl2IRUqHRdrS.zip

I opened your scene and saw the movement in the sim, but when I deleted the fracture’s keyframes and re-ran the sim on my computer it didn’t move before the ball hits it. I also got a fairly different sim then the one you got. Maybe because I didn’t modify your ball keyframes. And you also have keyframes for the fracture at frame 2 and on when you have reactor set to start at frame 8 (I guess you changed that after you ran the sim?). I still got a stable wall even if I change it to start at frame 2 though.

But if you’re happy with your sim when your fracture breaks, I would say delete the keyframes from right before the ball hits and lower the fracture down closer to the ground.

Attached is the scene with my sim in Max 2009.

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC

	Attachment
16610_y8KqTxvXycceD1lnKbdd.zip

Yes, you got it locked very nice! Is there a “clean up/reset button” in reactor or do I have to manually delete the keyframes? I will try to do a full “reset” and run the sim again. Be right back…

Regards / Jimmy

These threads talk about various ways to clear keyframes in reactor.
Link
Link

It might be easiest just to select the rigid bodies, select all their keyframes and hit delete. But if you have a lot of reactor things in your scene, take a look through those threads.

And another thing to do after you run your sim is select your rigid bodies and open the curve editor. In there you can go to Keys>Reduce Keys and that will smooth out some of your results and take away some of the jitters. But beware that you can’t stop the process once you hit OK and it could take a while.

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC