Magnet Rotation Bug?
- August 9, 2020
- 1 reply
- 992 views
Hi CA people 🙂
I think I've found a bug with magnets. Any advice would be really appreciated.
I'm doing something weird. I have a character with shoulder length hair, and I want the dangling hair to be on top of the shoulder, but I want the forearm and hands to be in front of the hair.
The way I've done it, is to make a normal arm with shoulder, elbow, wrist tags, bones, arm IK etc below the hair.
Then I made a copy of the forearm, and put it above the hair, and used a magnet with weld to parent the top forearm to to the one from underneath that has the arm IK.
It works well, in fact it kind of looks better, because the elbow isnt being mesh deformed anymore.
BUT, whenever the top forearm passes through a 180 degree rotation, it freaks out for half a second and appears in random locations in the frame.
If I pause the playback on that frame, within a second, the program fixes itself and the forearm returns to the right place, but on export, the frame doesnt wait to be be fixed before it outputs, and so I have these glitches, whenever the top object goes through a 180 degree rotation point.
Im am guessing that at that point the software goes from what would be 181 degree rotation to a -179 degree rotation, so that if you windmill an arm, you dont end up with 1000+ degree rotations, which makes sense, but the program freaks for just a moment as it changes rotation values from the 180+ value to the corresponding negative rotation value.
But on export, the program doesnt wait for the fix before exporting the frame - probably due to the real time nature of the program.
I could export single frames of the problematic frames as fixes, but that would take a lot of extra time.
Attached a video example.
The original arm is blue, and the green one is the one on the top layer that is magnetized to the blue one. The original position was horizontal with the hand to the left, so you can see between frames 5:04 and 5:05, as the object goes through the 180 degree rotation mark, it glitches for a moment, but then recovers.
I wish the export would wait for the recovery before writing the frame to the output file, or the glitch didn't happen in the first place. Either way would work for me.
Oh and so youre not confused, the blue forearm is invisible, which isnt affecting this, but thats why you dont see it underneath when the green one temporarily glitches.
Thoughts?
Bug fix?
Thanks for reading this and any thoughts you may have!
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