[PD] GEM Shear / angle relationship - sinusoidal error

[Ed Kelly]

Yes, that's what I meant to say. Radians is only for the [tan], but it's quite 
useful elsewhere.
I have been feeling guilty all day, for the archives being wrong-headed :) from 
me.

I have a nice trig patch now :) maybe I should submit a good trig patch to GEM 
documentation. Perhaps we could help - since many artists struggle with this (my 
math teacher at school was really intimidating!)

But, I have noticed a sinusoidal error with the graphics in my patch. So, here 
is the real thing!

It's my notation system. I was trying to keep it a secret until it is entirely 
ready, but open source projects demand open-source solutions, so here's the 
current prototype. Notice that when you move the second note up and down, there 
is a sinusoidal error in the [shearYX] -ed half-beam sheared rectangles. Is 
there any way to calculate this and compensate for it? I must have missed 
something...

...Classical players can be quite particular about such issues! I want it to 
look good.

PS - For the Brazilians I showed this to, I love you and will deliver this soon.

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



----- Original Message ----
From: cyrille henry <ch at chnry.net>
To: Ed Kelly <morph_2016 at yahoo.co.uk>
Cc: Claude Heiland-Allen <claudiusmaximus at goto10.org>; PD List <pd-list at iem.at>
Sent: Wed, 1 September, 2010 20:44:56
Subject: Re: [PD] GEM Shear / angle relationship



Le 01/09/2010 10:37, Ed Kelly a écrit :
> Thanks for unlocking my broken trig head.
>
> This should really be in the documentation. The angle is in radians. Patch
> enclosed...
no, the angle is not in radian.
in fact, shear is a non rotational space distortion, there is no angle...

shear distord 1 direction in relation to the coordinate on a 2nd direction.
As Claude explain, you can calculate an angle from this distortion, based on 2 
dimension. The tan object is in radian. that's the only thing in radian.

Cyrille



>
> 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
>
>
>
>
>
>
>
> _______________________________________________
> Pd-list at iem.at mailing list
> UNSUBSCRIBE and account-management ->  
>http://lists.puredata.info/listinfo/pd-list



      
-------------- next part --------------
A non-text attachment was scrubbed...
Name: testme.rar
Type: application/octet-stream
Size: 258877 bytes
Desc: not available
URL: <http://lists.puredata.info/pipermail/pd-list/attachments/20100901/ec7099b1/attachment-0001.obj>