Re: [Algorithms] Correct Way to transform direction vector

[Neal T. <ne...@ps...>]

From: Jason Zisk <zi...@n-...>
> Hey everyone.  I'm having a problem transforming a direction vector from
one
> coordinate space to another.  I need to transform the direction of the ray
> from world space to object space so I can do an intersection on the
> triangles in a mesh.
>
[snip]
> I looked back at the archives of this list and I noticed a discussion of
> transforming normals.  It seems that using the transpose of the inverted
> transformation matrix is the right way to transform a normal.  By doing
this
> I actually solved some problems (with scaling) but caused others with
> rotation.

What sort of problems with rotation?  Naively, I would have thought that the
transpose of the inverse of the 3x3 matrix would work, assuming you're not
doing anything really exotic in your transform...

Neal Tringham (Sick Puppies / Empire Interactive)

ne...@ps...
ne...@em...