Maya- Quadruped Rigging Help (stag, front legs)

simonelr

Hi all,

So I'm currently working on learning to rig quadrupeds, and I'm doing so on a stag model I made. I have been following a tutorial and it is till just now I realized an obvious error in why their tutorial wouldn't work for the front legs.

The model that the teacher is using is a dog, and obviously the front leg structure of a dog is a bit different to a deer (i.e , dogs don't have a "knee").

The layout of IKs for their rig is Rotate-plane IK (from "chest" to ankle), and single IKs from the ankle to paw-heel, and heel - toe), of course then, parented to a foot controller.

Unbeknownst to me, the anatomy difference at the time, that IK layout doesn't work for me given that the rig needs flexibility for the knee.

Could someone please help me or point me in the right direction of how I should set up my IKs for a deer/horse type front leg?

Here is my front leg set up ;

I'd like the front legs to be able to bend something like this:

(With the leg set up i described only the upper "shoulder" and ankles move, but not the knees which is what I need help with).

thanks

Alex_J

Edit : looked at my dogs, and their fore leg works the same as the deers, the knee is just lower down. The metacarpals are just much shorter. Thus, unless I am missing something, the rigging should be the same, only the position of the joints differs.

The anatomy is not so different. You are correct in a practical sense, but I think with a bit of critical thought you can come up with a solution just using what you have learned from the tutorial so far. Essentially, the deer just has an extra joint that bends the opposite direction from the others. So just work an extra joint into the hierarchy for now, and after you've set up the IK's and controllers for the "dog" joints, you should understand how to do the same process but reversed for that extra joint. Assuming you are a beginner (hench the tutorial), I wouldn't sweat the fact that after you rig the leg as per tutorial instructions you will need to do some overhaul to get that extra joint in there -- that's just more repetition and problem solving, which is a really powerful way to learn.

benjaminredman

I rigged a quadruped with a similar joint configuration and I found that using a Rotate-Plane solver IK still can work. Try attaching it to the joint closest to the "armpit" and the joint in the ankle. That way, you can have the forward-facing knee controlled with a pole vector constraint. This would allow for a more natural-looking deformation.

sharsein

Start by studying the anatomy of a deer skeleton:

Notice the angle of the scapula and humerus. This is what lifts the forelimbs up. Remember that deer and other hoofed animals walk on their toes, so their joints are higher than you'd expect. There is still a slight forward bend in their ankle too. So if I were to setup the IK on the ref image you posted, it'd look something like this (realized now I forgot to draw the connecting bones so this should be a joint chain not free floating joints but you get the idea):