[PD] GEM Shear / angle relationship

[Claude Heiland-Allen]

Hi Ed,

On 31/08/10 15:31, Ed Kelly wrote:
> Can anyone tell me how to calculate the 'shear' value (when using [shearYX] in
> Gem) from an angle (degrees or radians, I don't mind)?

This is just a guess, for one direction of shear in 2D space:

shear = tan(angle)  (the angle marked ** in the ascii diagram below)

|   __________
|**/         /
| /         /
|/_________/


(because tan(0) = 0, tan(45deg) = 1, tan(90deg) = inf)

Otherwise try drawing triangles and doing some trigonometry
(in a right-angle triangle:
sin=opposite/diagonal
cos=adjacent/diagonal
tan=opposite/adjacent
)


Claude
-- 
http://claudiusmaximus.goto10.org