RE: [Algorithms] How to derive transformation matrices

[Steve W. <Ste...@im...>]

> From: ro...@do... [mailto:ro...@do...]

[snip]
>    
> > If that is what you meant then a shear is
> >the perpendicular component of force on a surface. 
> 
> Although incompletely stated,  I believe you have this wrong.  The
> shear comes from the force component parallel to the surface, not
> perpendicular.
> 

uh...no, it's the perpendicular.  Forces parallel to a surface do not
interact with the surface (actually, there would be no resulting force for
any actions parallel to a surface) unless the perpendicular force causes
penetration so the parallel component then has something to "grab onto".