Proof Of Tech Quadruped Rig Part 2
IK Leg Set Up
In this second installment we are going to focus on building a basic Ik leg set up for our Quad Rig
Our First Step is to build our IK chain, we will start with Shu’s back leg as our first example.
I personally prefer to hide the poly while working with the joints, if you wish to hide the poly/geo go to Show>Polygons and unchecked the box
Now we must start building our IK chain go to Skeleton>CreateIKHandle>OptionBox
In the IK handle options we want to make sure we are using Rotate-Plane Solver under Current solver. This will allow us down the line to use pole vectors to make our elbow joint.
After that has been changed to Rotate-Plane solver we can start building the chain. In the rear leg our chain will be made up of 4 ik chains. Make sure under show that IK handles are visible. To make a chain you must select the top joint and then the lower joint in the chain, if done correctly a line will be seen between the two.
Hip joint – Ankle Joint
1Ankle Joint – Paw Joint
1.) Paw Joint – Toe Joint
toe Joint – Null Joint
Now with our Ik handles in its time to get into the Hypergraph. Go to
At the end of the page you should see your 4 IK handles
Now select all the IK Handles are group them together (CTRL-G)
You are then going to grab the last three Ik handles and group them together
We now need to move the pivots of the groups so they effect the leg correctly. Select the second group and move its pivot (SelectJoint>Insert to move the pivot) to the Paw-Joint (CTRL V to snap to joint). This will later act as the heel
Next we will group the last 2 ik handles together and move the groups pivot to the Toe-joint, This will later act as our Toe
Now we must select the first IK and Second IK and group them together. We will then move that pivot onto the Paw_Joint. This will allow the paw to stay on the group but still bend the ankle
Now we will select Group1 and create another group. We will then move that groups pivot to the end of the foot to act as a toe pivot.
Now that our Leg IK is working we should rename all our groups
Next we need to create a Foot Controller, create a nurbs circle and move it to the back foot. Make sure to freeze transforms delete history and rename the curve L_BackFoot_CTRL
We can now parent our grouped IK chain under our foot Ctrl
Our next step is to add attributes to our leg Controller.
Go to Modify>Add Attributes
We will now create attributes for each group we made in the hypergraph with a default of zero
All Attributes should now show up in the channel box for the foot controller.
Now we must connect our new attributes to the correct groups. To do this we must go into the connection editor.
Windows>General Editors>Connection Editor
Next we want to load our foot controller on our left side (Have it selected and hit reload left). At the very bottom you should see the attributes you created. Now you can load each group into the right side and connect the rotate x
You can now repeat the same process for each group
In the pics my IK chains were in the wrong order here is the correct order
If all done correctly your attributes should now be able to drive your leg IK