Comments on: Readings 1: Rotations and Transformations

By: raja

raja — Wed, 26 Jan 2011 14:32:00 +0000

This reading exercise might have the best set of articles/papers, ever!
I loved the explanation of rotations & orientations, and why some representations don’t work or are not good (Gimbal lock, non-smooth interpolation, too much state/constraints for less degrees of freedom, etc). The reason behind wanting different representations for a rotation and an orientation was beautifully presented as well.
The notion of commutativity, torque-minimal & constant angular velocity and how different quaternion based interpolation mechanisms slerp, nlerp & exponential map satisfy only 2 of these properties was quite interesting, though I could get only a gist of the idea.
The importance of interpolation (which, somehow, i’ve always downplayed) really struck out through this reading.
I skimmed through a bunch of the articles and lost my way in visualizing hyperspheres..

By: Leslie

Leslie — Wed, 26 Jan 2011 14:15:45 +0000

In reply to Jim Hill.

I totally agree, actually applying what we read will be very helpful in understanding it.

I noticed that I was able to get a high-level understanding of the material from the papers I read, but about halfway through each paper I hit this wall where I guess the authors assumed some background knowledge that I don’t have yet, and I was no longer really able to follow mathematical details.

(I read the first paper and Shoemake’s paper)

By: csv

csv — Wed, 26 Jan 2011 11:52:36 +0000

I found the article “Understanding SLERP and not using it” extremely useful. I have read many text books creating the impression that SLERP is the ultimate in
interpolation. This article was really eye opener for something we take for granted.

By: Jim Hill

Jim Hill — Wed, 26 Jan 2011 01:29:46 +0000

One thing I think I picked up from the first article is what makes rotations and orientation different.

One thing that I’ve found about this kind of stuff is that doing it makes it sink in more than reading about it. I remember the roller coaster project in 559 really made me think about rotation and orientation in order to get the track to bank correctly. I think I’ll probably have to do something like that for quaternions and rotation vectors.

By: gleicher

gleicher — Sun, 23 Jan 2011 22:05:34 +0000

In reply to David. The Murray,Li & Shastry link should now be to something for which your CS password works.

By: sghosh

sghosh — Sun, 23 Jan 2011 21:37:40 +0000

Same problem in here.

By: David

David — Sun, 23 Jan 2011 21:25:42 +0000

The link for Chapter 2: Rigid Body Motions requires a password, and I’m not sure what to give it. Neither my CS or WordPress account worked.

The gamasutra.com link is dead.