View Full Version : Bullet Bug in 2015?

03-01-2018, 12:04 PM
Hey Everybody,

I've been trying to learn how to use Bullet to animate dynamic hair. I'm almost there, but I've run into a strange problem. I've got a character, hair object, and all the proper settings to animate the hair the way I want, but one thing that's also needed is Proxy collision objects for the hair to interact with.

I created 6 proxy objects and parented them to the head, chest, shoulders and upper arms of my character. These are needed to keep the hair from passing through the character's geometry.

Now, before I enable Bullet, the proxy objects follow the motion of the character perfectly, but once I enable Bullet, they start twitching and jerking around randomly, so they are not only not in the right place to interact with the hair, they actually swat the hair and disrupt the hair's motion that I'm trying to achieve. :cursin:

Please watch to the video below and you'll see what I mean. The problem is especially troublesome with the chest, head, and right shoulder.

Is this a bug in Bullet? Once I turn off dynamics, the twitching goes away. Anybody know what's causing this? Any idea how to stop it? :stumped:

Thanks in advance,


03-03-2018, 10:54 AM
I spoke to Newtek tech support and they said the recognized the problem. He suggested downloading the demo for 2018. I'm running tests now, and so far, the twitching problems with Kinematic objects has not resurfaced.

I'll keep everybody posted.

03-08-2018, 06:10 PM
Okay, I upgraded to 2018, and the problem seems to have gotten better, but it is still happening.

Below are two clips where you can see what happens to my proxy objects when Bullet is on and off.

Any idea what causes this and what we can do to stop it?