[Plugin] Leap Motion - Event Driven

[Slayemin]

@;310971

I’m glad you’ve asked the question, I was hoping someone would dig deep enough to ask about the implementation. The change basis function rotates all the AnimBody bones (that are parented, so if you rotate the body it will rotate all the bones) to a new basis. Pre-rotation applies input rotation before you’re in the new space so it will affect all of your input rotations. In contrast post-rotation only rotates it by a constant amount and will not affect the basis of the input.

The reason for doing all of this is that in component space (e.g. character blueprints) X is forward Y is right, Z is up; but in animation Y is forward, X is left, Z is up. So in order for everything to appear correct we need to change the rotation space to the new Y = Forward orientation. That is all that function does.

Okay, I get the FABRIK and Two bone IK stuff. I’m still really stuck on the basis change stuff though.

I’ve got the left hand working perfectly, but I’m using different left prebase values and post base values:
Left Prebase: 90,0,0
**Left Postbase: **0,0,0

I don’t know why, but that works. Your values are different:
Left Prebase: -90,0,0
Left Postbase: 0,0,-90

The right hand is different though, and I’m stuck at the relationships between rotations:

I’m using the exact same values you’re using within the LeapBodyConnector and I get wrong results:
**Right Prebase: **90,0,180
Right Postbase: 0,0,90

Through some testing, I was able to find:
**Right Prebase: **-90,0,-180
Right Postbase: 0,0,0

This puts my elbow and palm in the correct position, but the right hand fingers are rotated 180 degrees (roll) in the wrong direction, and the thumb goes into the palm.

What’s causing the difference in our pre and post basis values?