[PD] GEM Shear / angle relationship

[Ed Kelly]

Thanks for unlocking my broken trig head.

This should really be in the documentation. The angle is in radians. Patch 
enclosed...

Best,
Ed

 Metastudio 3 for Pure Data - Free download at:
http://sharktracks.co.uk/puredata



----- Original Message ----
From: Claude Heiland-Allen <claudiusmaximus at goto10.org>
To: Ed Kelly <morph_2016 at yahoo.co.uk>
Cc: PD List <pd-list at iem.at>
Sent: Wed, 1 September, 2010 1:09:43
Subject: Re: [PD] GEM Shear / angle relationship

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



      
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