• Advertisement
Sign in to follow this  

Question

This topic is 4364 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Is the inverse of an orthonormal basis always equal to the transpose?

Share this post


Link to post
Share on other sites
Advertisement
Indeed. This is one of the many optimizations you can employ when working with 3x3 rotation matrices (or a 4x4 transformation matrix, as long as you handle the rotation and translation components separately).

Share this post


Link to post
Share on other sites
That's nifty. I saw how gluLookAt worked and wondered why they constructed the matrix that way.

Which is a better coordinate system, left-handed or right-handed? Which is more popular?

Share this post


Link to post
Share on other sites
Quote:
Original post by Boder
That's nifty. I saw how gluLookAt worked and wondered why they constructed the matrix that way.
Note that the gluLookAt() implementation is based not only on the inverse-transpose equivalency, but also on the property (AB)^-1 = B^-1*A^-1.
Quote:
Which is a better coordinate system, left-handed or right-handed? Which is more popular?
That's sort of unrelated, but basically:

1. DirectX is LH but offers RH versions of most functions
2. OpenGL is RH, but can probably be coerced into being LH by constructing your own matrices
3. I think most math and physics references assume a RH system
4. I don't know what the various modelling programs use, but google will probably tell you

Once you understand the underlying math, switching back and forth between the two when necessary isn't too hard.

Share this post


Link to post
Share on other sites
Quote:
Original post by Boder
Which is a better coordinate system, left-handed or right-handed?


Neither is better. The question is akin to "which is better, clockwise or anticlockwise?"

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement