Hi! I trying to generate a crowd of stones falling to the ground. Everytime I do a simulation I always get some stones that’s doing some crazy rotations or never stop to move. What is the parameter to tell objects to “die” when reached a specific value. I suspect the two behaiviors is related, or?

Regards / Jimmy

"Add Deactivator” in the Havok World rollout does this, you may want to alter the frequencies there.
Also, you can select a bad stone, and manually delete it’s keys after a certain point in time by region selecting them on the time bar or in track view.

If your sim was done in Reactor and after you create the animation you get funny rotations and nervous jumping in geometry, change the rotation controller from Euler to TCB in each of these shapes. I usually set TCB to default before running any sims, specially if it involves Fractures.

Hi! I tried to alter the frequencies in “Add Deactivator”, but it seems to have no impact. Can’t find any info in the help about the Deactivator how to set it up. Is there a specific combination and/or is the values depended on the world scale?

The two methods that I get to work is:

1. Manually delete/change the keyframes. It is very clear where the simulation go bananas so it’s easy to find and fix, but it takes a lot of time.

2. Change the rotation controller from Euler to TCB. This fix it automaticly. The only thing that’s a problem here is the change of controller. How do I change hundreds of objects?

Many thanks for the tips, it saved my day!

Regards / Jimmy

This is what Help says about Add Deactivator.

Add Deactivator
When on, reactor adds a deactivator to the simulation.

The deactivator keeps track of the objects in the simulation and deactivates (stops simulating) objects that it determines are at rest. This keeps reactor from wasting system resources simulating objects that aren’t doing anything.

When Add Deactivator is on, you have access to two distance parameters for determining whether an object is moving or not. The reason that there are two properties rather than just one is for bodies that vibrate. It’s possible that a body can end up vibrating after a collision or some other occurrence. A vibrating body might vibrate a few millimeters in distance, which would keep it active for a typical Short Frequency test. However, the object is not really moving anywhere, so keeping it active wastes CPU time. However, if it vibrates in place, it fails the Long Frequency test and is deactivated.

Short FrequencyThe minimum distance, usually in millimeters, that an object must move during each step of a simulation. If an object in a simulation does not move the specified distance in each step, reactor deactivates it.
Long FrequencyAlso sets a distance, usually larger than the Short Frequency value. Long Frequency checks every few steps simulation rather than at every step. Any object that does not move the required Long Frequency distance is deactivated.

An alternative to changing the controller is to change the key type. It may be the sub-frame interpolation of the keys causing it. Region select a whole bunch of keys at once and change to Linear instead of Smooth. Or you could change the type before the sim.

Thanks Samab! Seems that I have to learn some basic search technique. I just can’t find it in the help files....

Now that I know that’s mm I can find out why it would not work. From what I understand this is for position and not rotation, right?

I will try to change the interpolation type tomorrow!

Regards / Jimmy