Ok, so i tried rigging the dog based on the tutorial and came up with a pretty good attempt except the legs kept rotating right out of shape. So i watched the instructional video and followed it step by step - with the same result. Everything just twists wildly in pose mode. I tried to adjust the pole target angle in the IK modifier but the rear leg is all out of alignment - either the shin is straight and the thigh twisted, or vice versa, and now the whole spine has shifted off the centre line. Everything looks fine in edit mode.
Screenshots are below:
All good in edit mode.
Not too bad in pose mode, side elevation, although the rear thigh is out of alignment and the pole target is almost off the page trying to contain the chaos.
Pose mode, plan view - everything has twisted to blazes and i don't know why. It's the rear leg but i did everything the same as the front.
Is it something to do with bone roll? I've tried to align the axes but don't really know what i'm doing or why it's necessary.
Any help would be gratefully received.
Hey stephensamuels , this happens to me pretty much every time I haven't done rigging for a while and then come back to it. So don't worry, it's an easy fix! The rig freaking out is definitely caused by the IK setup, I don't think the bone roll would cause that much of a problem. It's hard to tell from the screenshots, but the IK bone should not be attached to the chain or have any parent - it needs to be completely independent. Otherwise, it's creating a closed dependency loop where the rotation of each bone depends on its own rotation, so rotating just a tiny bit will twist them all to approximate infinity.