View Full Version : Having a little Bullet cloth dynamics issue

01-22-2014, 11:30 AM
I've read and searched but am not turning up clues as to why I'm having this issue.

I have a rigged character that has a capsule formed to fit around the body, parented to the spine. That is defined as a kinematic body.

I have a necktie positioned with the upper tip at the desired place on the character's collar (inside the "knot"), parented to a bone that extends from the neck bones through the tie's knot.

When dynamics are activated, the tie flops down and rests against the front of the character very nicely. The problem is if I move the character at all the tie stays where it is instead of moving around with the parent bone. I also tried adding a null and parenting that to the bone instead and parenting the tie to that null. No help.

What do I need to do to a deforming body in Bullet so it "sticks" to the parent object and moves around with it in addition to flopping cloth-like?

Many thanks in advance!

01-22-2014, 12:30 PM
Okay, this is getting frustrating. I switched away from the tie to try adding a cape. Now the cape seems to be honoring its parenting to the bone I selected (why it suddenly started I do not know), but the body capsule, a kinematic object, stops moving with its parent as soon as I add the bullet property. And sometimes while messing around with setting and resetting the parent the capsule will jump to new positions.

Attached is the scene I'm trying to work with, does anyone have an idea what I could be doing wrong? Is this some kind of buggy behavior in Bullet?

Many thanks in advance.


01-22-2014, 01:24 PM
Okay, it appears to be more of a screen refresh issue. While messing around with it I noticed that sometimes the body capsule would jump into place during movement, and if I set a camera to track it that would always point at the character. Okay, getting somewhere.

01-22-2014, 01:53 PM
Just gonna vent for a second: when you're working away trying to get a handle on a new feature (I'm still struggling with getting a good technique down with bullet cloth) it is endlessly frustrating to have bizarre behavior manifest itself, such as makes you think something isn't set up right. I guess when I'm more accustomed to Bullet's quirks I'll realize when I have an actual issue and when it's just acting up and needs several resets.


Okay, back to work.

01-22-2014, 10:22 PM
I must say I return to the old fx tools sometimes, probably I'm not used to Bullet yet to facing some kind of "whatthehellisgoingon"

01-23-2014, 07:31 AM
Yeah, Bullet seems to be an acquired taste. I used Bullet cloth last year on a piece that needed a flapping scarf and I don't recall it being this twitchy, but it was only one dynamic object and in my current one I have four plus two forces so there's that. I've learned that when it starts behaving oddly just disable dynamic, reset, and re-run the calculations--once or twice I also have to restart Layout when a glitch is particularly stubborn.

Now that I have a better handle on what is my goof and what is just Bullet acting up I can work with that.