Bone Setup for a Dragon
In your hypergraph, pelvis should at the top of the hierarchy.
To make the pelvis joint more easy to select, I will select the pelvis joint and -> Display -> object component -> Selection Handles to display it��s selection handle. Then, toggle toSelect by Component mode, select +.
Then select pelvis's selection handle from pelvis joint, moves it away from the pelvis joint. When this done, we will be able to select pelvis joint easily.
Reorienting Local Axes of Joints
To show joint's local rotate axes, select the joint, go to Display -> object components -> Local Rotation Axes
As you can see from the bone I've created with local rotation axes shown, Y-axis is pointing down the bone, This is what we want. But after we translate the joint to fit it into our model, Y axis will no longer pointing down the bone anymore, and this will mess up the joint's rotation, this is what we don't want.
So, we need to reorient the Y-axis. To do this, we need a MEL command to help us auto reorient the Y-axis. Key this joint -e -oj yxz -zso -ch; in command window, you can edit yxz to xyz to suit your need. First alphabet is the axis that pointing down the bone. You may like to save this command in your shelf by MMB drag the script from command window to shelf
We will use another Mel command select -hi; to help us to select all joints in hierarchy. Save these commands into your shelf, it's very useful.
1. Pick the pelvis joint and apply select -hi; to select all joints in hierarchy.
Go to Display -> object components -> Local Rotation Axes to show all joints' rotation axes.
2. While the bone still selected, I applied joint -e -oj yxz -zso -ch; to reorient the joints.
Check the joints�� reorientation carefully, if everything ok switch off display local rotation axes.
Now, I have our bones ready. Next, I will proceed to IK setup.
1. I will start with its left leg, for the leg joints, I turn off some joints axes Degree of Freedom. To do this, select a joint and open it��s Attribute Editor window (Ctrl-A). Do this to the joint that you think has only one or two rotate axes
2. Then, I will proceed to create IK. Select the IK tool: skeleton -> IK handle tool or select from the shelf.
From the IK Handle tool option, switch the Current Solver to ikSCsolver.
3. With the tool still selected, I clicked on the left leg��s joints that I wish to apply with IK.
4. You will find an IK handle node in your hypergraph. Rename it. Press Y to return to previous tool, then I create IK handles for both of the toes. There are total 3 IK handles I created for left leg.
You can start move around with the IK handles to see how IK works with your bone. Undo the translation to get it back to position before moved. O.K, now select the pelvis joint, translate it, you may find that the left foot was moved with it. We would like it to stay on the ground. To do this, we need to add locators to control it.
5. Create a locator and holds down V key to activate point snapping, then MMB drag the locator to heel joint. Then create another 2 locator, using the same way to place it to locations of toe1 and toe 2. Rename the locators. Then parent the locator to its IK Handle.
Now I will select the pelvis to move around, the left foot be stay on the ground.
6. Using the same method to apply IK to right leg.