Monday, 9 November 2015

Proof Of Tech Quadruped Rig Part 2 IK Leg Set Up

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
Windows>Hypergraph Hierarchy

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

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