1) "Even Divisions" - This option ignores the length of bones when considering how they should fit along the curve. This is useful for getting a smoother curve fit without having to worry about getting the bone lengths spot on. By default, this is disabled.
2) "Keep Max Length" - This option prevents the bone chain from extending past its natural length when the spline is stretched beyond that length. When the spline length is substatially shorter though, this bones get scaled to zero; making this option possibly useful for doing "growing tips".
This is essentially a 'no scale' option, although the behaviour when the curve is shorter is really a compromise since the curve cannot be accurately satisfied + left intact without some scaling being applied due to the way this works.
3) "Radius to Thickness" - The average radius of the spline between at the head+tail of each bone determines the x+z scaling of the bone.
At last, this commit introduces the Spline IK Constraint to Blender. Spline IK is a constraint that makes n bones follow the shape of a specified curve.
Simply add a chain of bones, add a curve, add a Spline IK Constraint to the tip bone and set the number of bones in the chain to make it work. Or, try the following test file:
http://download.blender.org/ftp/incoming/250_splineik_spine01.blend
Screenshots of this in action (as proof):
http://download.blender.org/ftp/incoming/b250_splineik_001_before.pnghttp://download.blender.org/ftp/incoming/b250_splineik_001_after.png
I've implemented this in a similar way to how standard IK solvers are done. However, this code is currently not an IK plugin, since I imagine that it would be useful to be able to combine the 2 types of IK. This can be easily changed though :)
Finally, a few notes on what to expect still:
* Constraint blending currently doesn't affect this. Getting that to work correctly will take a bit more work still.
* Options for not affecting the root joint (to make it easier to attach the chain to a stump or whatever), and non-uniform scaling options have yet to be added. I've marked the places where they can be added though
* Control over the twisting of the chain still needs investigation.
Have fun!
Contributors list isnt used much in our C code so probably its easier if people just use svn blame for this.
Can change if this isnt acceptable but I guessed people didnt care so much since most scripts had no header.
