Reply To: IK bone properties tab
Hi Harris,
Yes Dwayne is spot on (I feel like I say that nearly every day haha)
Personally I don’t use the locks, stiffness or limiting of the range of motion. I use constraints for this – as I feel it’s 1 less thing to have to learn and worry about.
It’s like the “inherit rotation” checkbox. I used to use this a lot when I first started rigging. But now I think it is much smarter to use constraints for this. Less to think about plus you can visually see that the bone is being affected and know it’s a constraint. (the checkbox means you have to go digging to see this)
As for the freedom aspect – yes yes yes
You want to leave things open for the animators where ever possible – only lock it down if it breaks the rig. If they make the rig look bad when it’s possible for it to look good – that is totally on them haha.
But having the freedom to do things that you didn’t think an animator would need to do is helpful. Animators can find really clever solutions to problems, but if you lock stuff down because “it physically shouldn’t do that”, then you are more likely to have a rig sent back to you so that you can implement a solution for them. (which usually means removing that stuff you added to ‘protect’ them)
As for the abrupt stopping on the IK chain – that is a known issue with IK. It’s a mathematical property with geometry.
Mathematical explanation:
Do you remember Tan for maths class?
Do you remember what it looks like?
Do you see how the curve flies off to +- infinity at all those asymptotes?
Imagine you are moving the IK control at a constant speed. The ‘knee’ will increase in speed as it gets straighter and straighter (even though the control is moving at a constant rate).
Therefore the knee’s acceleration approaches infinity the straighter the leg gets.
Normal person explanation:
The knee will pop.
You might see some “soft-IK” solutions to mitigate this, but that just alters the way the deformation bone follows the control (it will loosen control as it gets straighter)
That might sound cool, but really it means the Foot isn’t where you want it to be so you have to animate it past that point because it starts to lag behind.
So if you need to deal with a popping knee, or a foot that isn’t where you put it – which one is better?
Personal preference.
Anyway – this was much more that I wanted to write, and I even got Pythagoras involved. What.
Hope this helped.