# How to limit the rotation of knees, feet, ankles and similar joints?

Is there any trick to prevent bending of the knees, ankles and alike so they stop at a certain rotation point, let say 45 degree angle? I have a character that I'd like the joints to stop rotating "naturally" so it doesn't look weird. The same goes for the knees, feet, ankles, arms, etc ...

See ref imgs and attached .blend file:

.blend file is 37MB and maximum limit is 30MB on blend-exchange.giantcowfilms.com so here's the link: http://we.tl/TFb1T7WNoV

No python scripts please. I'm a total noob.

• There's a way to limit rotation on IK chains, and there's another to do it on FK chains. But I don't quite understand what your image is saying. The distance and position between the hips and the foot is very different between the two poses. I don't understand how you can expect the right bending on the left pose. – Antonio Buch Feb 28 '16 at 17:15
• @AntonioBuch For human bones it's impossible to bend it after a certain point. Let's say the knee can't bend backwards cus it would break. The same thing goes for the elbow, fingers and etc. I'd like my characters fingers to behave like human bones. So in real life, if my finger bones bend too much the wrong way they would break and I have to go to the hospital ;) – Michael Hansen Feb 28 '16 at 17:19
• The common approach to this is that the animator don't push the rig so much. Not pretty fancy actually, but it's the usual behavior. For instance, you can see plenty of animations with the fingers waaaaay rotated on the opposite direction. In this case, it helps with the pose appeal. For me, limiting is a disadvantage. – Antonio Buch Feb 28 '16 at 17:23
• @AntonioBuch In the ref img the ankles are bent in an abnormal way since the foot is placed on the ground and the knees touching the ground at the same time. In real life that's not possible, right? – Michael Hansen Feb 28 '16 at 17:24
• BTW was that rig made with Blenrig? – Antonio Buch Feb 28 '16 at 17:24

Edit: In looked back at this old answer and realized you were using an IK rig. To limit this, there is an inverse kinematics section to the bone properties.

Select the bone you want to constrain, and make sure you are in posed mode. There should be a bone constraints window:

By check boxing 'limit' you can set a bone to only bend so far in IK mode.

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  Old Answer


You can add a "limit Rotation" constraint, as you can see set up there. It also has other bone limitations; go ahead and mess around with it.

I'm not 100% as I've not used this in the more recent versions of blender, but I believe that in the "properties" window, under "bone costraints", if you "add bone constraint2 and select the type "transformation", you can input the bones max and min x,y, and z rotation.

I hope that helps.

• I've tried your solution and it doesn't seem to work. Or your explanation is not sufficient enough for me to understand. Please open the .blend file and be a 100% sure in your answer. – Michael Hansen Feb 28 '16 at 17:15
• Looking at your image, your rig looks a lot lot more complex than the simple armatures I have used, so it might be that my answer was incorrect or not helpful enough. I apologize that I could not help more, I am only an amateur myself. – Jennifer Feb 28 '16 at 17:22