Lesson 3 - Spine

Much the same as the previous examples, the spine is a combination of IKs, Joints and Controllers. Some aspects have changed from the arms and legs so I'll explain the process in closer detail as we get to them.

Start by creating a spine using joints. Use around 6-7 joints in the chain starting from the pelvis heading up towards the spine. It might be easier to snap to the grid to make it straight.

It can be easier to visualise the spine by adding a mesh around the joints. In this case, I used a cylinder. Next we'll add an IK to the joints however we'll use an IK Spline Handle instead of a normal handle. Open the options tab and change the settings to these:

Place the IK from the bottom joint to the top. In the outliner you should now see a curve. Isolate the curve and right click it until you get the Marquee menu. Go to 'Control Vertex'. You'll now see 4 points across the curve.

Highlight the top two and go to 'Create Deformer > Cluster'. Do the same with the bottom two. You should see small 'C's on the curve. These are Clusters, they are useful for collecting objects to move together. Move the pivots of these clusters. The bottom cluster should be on the bottom joint and the top just below the pecs.

At this point, add the mesh around the spine. Just a cylinder will do in this case.

Now we'll skin the torso. This means making the bones affected certain parts of the mesh. We'll cover skinning in a later tutorial. For now go to Skin > Smooth Bind.

Create two controllers, attach them to where the clusters are pivoted. Freeze and name. Next, parent the clusters to the corresponding controller.

Add an attribute to the bottom controller called Twist. On the IK Handle is an attribute called 'Twist'. SDK this to the attribute (Have -10 and 10 as Min/Max values).

For the other controller, the cluster should be controlled by the rotation of the controller.

You should now have a spine that affects the mesh!