Forums > Jitter

gridshape rotatexyz behavior

October 11, 2010 | 8:21 am

When using rotatexyz, a change in rotation around the X axis doesn’t affect the orientation of the Y and Z axes; the Y axis is always up and down and Z is always front to back. However, a change in rotation in the Y axis does affect the X axis orientation, but not Z. Furthermore, a change in the Z axis affects the orientation of both X and Y axes. What I would like to do is have rotation be completely relative. In other words, I want the X value of rotatexyz to always flip top to bottom in relation to the camera, regardless of Y and Z values. I’ve been trying to work around this strange behavior of rotatexyz and can’t seem to wrap my head around it. Is there a way to keep rotation strictly relative to the camera? Attached is a basic patch to test what I’ve described.



October 13, 2010 | 1:20 am

Sorry, I can’t check your patch on this computer but it sounds like your describing a type of "gimbal lock"? Can you add another gimbal(degree of freedom)? There are objects for easy conversion to quaternions.

October 15, 2010 | 7:08 am

After some more research I can say it is totally the "gimbal lock" problem and I believe I can achieve what I want in my patch using quaternions. Thanks for pointing me in the right direction. :)

By the way, I stumbled across this in my searching and had my mind blown:

Probably old news to most of you forum folks, but I thought it couldn’t hurt to spread the word to those who haven’t seen it yet and stumble upon this post. Amazing work Wes and Graham!

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