jerky movement - bone snapping

[Slimj]

Hello!

I'm wondering if someone can offer me some advice to a fairly new Moho user (couple of months) about problems with the bones in my rig snapping straight, then bending slightly, repeatedly during a movement. I've tweaked the graph editor for hours and I'm still not fixing the problems. I'm also having problems with the movement being jumpy, especially when I'm creating cycle loops. Again I'm going in to the graph editor but I can't smooth out the motion. Just can't seem to get a tune out of my rigs at the moment. Any help would be much appreciated!

Here's a link to the Moho render and the Moho file (13.5): https://we.tl/t-d1Fc14ZjgB

Cheers
Jamie

[Greenlaw]

Hi Jamie,

I can't seem to access your file without signing up for a WeTransfer account, which I'm not going to do, but I might have an idea about what's going on.

Based on the info, it sounds like Moho is having an IK conflict in the joint, meaning it doesn't know which direction to bend the joint, so it goes back and forth. To correct this, you need to give the joint a slight pre-bend at frame 0. This should be in the direction the joint will most commonly bend. You can leave the artwork straightened; just bend the bone joint slightly.

To change the 'preferred' IK direction during animation, you can alt-drag (temp FK mode) on the bone to add a counter rotation. This will tell Moho's IK to bend the joint in the new direction. This is a common way to animate a rig in Moho to prevent IK jitter and pops.

As for creating cycles, I always use Freeze Pose at the first key and copy that to the last key. This ensures that the cycle's end frame matches the beginning without being affected by keys outside of the cycle. Then I make sure the cycle's end frame points to the second frame in the cycle. You need to do this so you don't get a double exposure at the ends of the cycle. Moho will maintain this cycle until you make another keyframe down the timeline.

Hope this helps.

[Slimj]

Thanks Greenlaw - much appreciated. I can try all of your suggestions. I was aware of the slight bend idea to tell the IK which direction to go so I made sure to put that in from the start. Strange about the We Transfer that's never happened before. There should just be a download button. Thanks for trying though!

[Greenlaw]

Strange about the We Transfer that's never happened before. There should just be a download button. Thanks for trying though!

Ah! The link destination appears to have changed. Previously, I was getting a signup page every time I clicked it but now I'm getting a page with a download link. I downloaded it and will check it out later today.

[Greenlaw]

Another thought: When you're using IK, it can help to enable the stretch constraint on the limb. In some situations, this can keep the limb steady when it's straight, and smooth out the transition when changing directions.

The decision to use this option can depend on the character design and the animation style you are going for, so experiment to see if it works for your situation.

[Slimj]

Thanks again Greenlaw. I will try out those tips and post again how I get on. Much appreciated!