Monday, 31 October 2011

Building the arms for the alien

This is an area where I tend to fall short when I'm rigging, so when it came to putting the joints in the arms, as well of the relevant controls, I would have to follow the relevant part of the Digital-Tutors tutorial to the letter.
 I initially started with three joints for the shoulder elbow, but I remembered to put another in the forearm, as I would need to set the IK handle here and then extend the effector to the wrist.  This is because the IK would only need to affect up to the forearm, as the wrist would have its own controls; however, at the same time, all the controls would need to be at the wrist in order to make it easier for the animator to operate.
Of course, I will now need to make sure that these joints are inside the arm and also positioned in a way that it wil bend accurately.  In this video, I found that the joint was actually outside the arm, so I just repositioned the joints, similarly to how I did the leg.  See this video.
video
Another important part was to make sure that the local joint rotations were all in order and that they were all straight.  I did this by hitting Fn and F8 to check the rotations of the joints.  As you see below, all of the joints in the forearm are straight as they are all aligned with the X, Y and Z axis perfectly.
 The fingers, on the other hand, were a little out of line and had to be rotated slightly so that they could be as in line as possible.
 Checking the local rotations was something that I got the hang of fairly quickly, the next stage was to insert an IK handle to create that bend.  The bending point would have to be in the elbow, but the wrist would have to be free to move by itself.  Therefore the effector could only affect from the shoulder to the forearm.
How I did this was by clicking the starting point at the shoulder and then clicking the forearm to insert the handle.  Even though this handle was not going to impact on the wrist, it would need to be located at the wrist; as all of the controls for this arm would need to be based there.

In this video, you will see me relocating the effector to the wrist, using the Hypergraph.
video
Now, I can use the IK handle to move and bend the arm.  It is an IKRP so this means I can rotate the arm in several directions.
 Before moving on to the next stage, I needed to create some controllers that I would constrain a little later.  This wrist control, which will be used for moving the arm in IK mode was made simply by importing another cube and reshaping.
 I needed a shoulder control to move the shoulder up and down, so I just created this S curve using the same method I used for the Pole Vectors in the leg.

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