[Soc-2005-dev] Inverse Kinematics

[Ton Roosendaal]

Hi,

> Well, my proposal is to have 3 checkboxes to disable/enable the
> X/Y/Z DOF's, and 3 upper + lower limits for their angles, just like  
> most
> other apps.
>
> The difference from Euler angles would be in how these values are
> interpreted. Euler angles are three sequential rotation (in blender ZYX
> I think). What I propose is:
>
> Y (roll) is always the last rotation, after a swing over the X and/or  
> Z axes.

Well... then it's a local transform, so actually you do it first (pre  
multiplied). :)

> If both X and Z are enabled, the swing part is defined as a direct  
> rotation
> (axis-angle) to compute the x and z parameters. Otherwise, the swing
> part is a simple rotation over the X or Z axis.
>
> This would only affect the interpretation of the upper/lower limit  
> values.
>
> Advantages:
> - parameters are more intuitive
> - singularity at 180° instead of 90°
> - no weird rotation order switching to avoid singularity

I don't get the 'swing' then, it will get 2 parameters (for X and Z).  
Will that enable an oval swing 'space' or so?
But sound good to me!

-Ton-

------------------------------------------------------------------------ 
--
Ton Roosendaal  Blender Foundation ton at blender.org  
http://www.blender.org