As Shiu mentioned, it would be helpful to hear more about the use cases where the new options would be applied.
Potential options:
1 bone IK
1) don't stretch,
2) stretch longer (not smaller),
3) stretch smaller (not longer),
4) stretch longer and smaller
2 bone IK
1) don't stretch
2) stretch longer (not smaller)
Currently we only have the 2 bone options. The 1 bone options could be 2 checkboxes, maybe Stretch
and Compress
.
A similar request was made here, additionally asking for uniform scale. This is turning IK constraint into a "distance-to-scale" constraint. While that is likely useful for some things, it may be better to have a separate constraint for tying together different transform properties rather than overload IK. IK is primarily about adjusting rotation so the tip of the child-most bone is closest to the target. By using a new, separate constraint for distance-to-scale it can be made more configurable (eg, limits and other options) without cluttering IK constraint. Still, it would be helpful if you can describe use cases for IK with uniform scale.
I forgot to add: you can simply use a small scale (or a short bone) with the current Stretch
checkbox to achieve an effect similar to 1 bone IK #4
above. That makes the only setting not currently possible out of all 6 is 1 bone IK #3
.