The main body part or areas we are going to divide the rig into are: spine, neck and head, eyes, legs, arms and hands.
We will develop the animation rig first and later the deformation rig for each area. In the next tutorials when we develop each rig area and explain it properly in detail, we will speak first about the placement of the bones and after about the angles of rotation for each bone and how many controls we will need to animate each area nicely, and last about the deformation rig and how to get nice deformations. Fig.12 and Fig.13
Good practice is to take screenshots from your model and draw over them. Try to figure out the ideal location of the bones and where to place the controls. Don't worry about deciding it right now; we will see how many controls are needed and where to place the joints in the next chapters.
You have seen the FK and IK words in previous images. FK and IK are two ways of controlling a chain of bones.
FK is the shortening of forward kinematics; meaning that we rotate each bone of the chain to achieve the desired shape.
IK is the abbreviation of inverse kinematic; instead of having to rotate each bone, you have a helper at the end of the chain and moving it will make the whole chain of bones to rotate and follow that point.
FK and IK are the base for rigging, and you will see these two words a lot of times in the coming tutorials.
Each one has its strong a week points and is better for certain type of animation. We will combine both and use whatever suits best for each case (Fig.14 and Fig.15).
A man waving his arm is the perfect use of FK. A walk is the perfect example for IK. One foot must stay on the floor as we move the character's hips. With FK this would be quite difficult to keep the foot on the floor while we animate the hips, we will have to rotate each bone to make the foot stay in the floor, and this will happen every time we move the hips. With IK this is done automatically.
But the legs of a character hanging from a helicopter would be much easier to animate in FK than having to animate in IK as it helps when following the movement of the helicopter.
Prototype and Clean Rigs. Test your Rig.
Prototype and Clean Rig
We test several solutions while building a rig. The result of all that testing is a number of unnecessary objects that were created with a certain purpose but now they aren't needed any more.
Once you have finished or you are happy with your rig, creating it from scratch again will help you to understand your rig better and to avoid unnecessary objects.
Often you want to test a new idea for a new part of the rig; it is good practice to do it in a clean file and once this is fully tested, redo it in the main rig file. Fig.16
Test your Rig
Before we hand over our rig to an animator it is always important to test it. Put the rig in situations you wouldn't expect - move, rotate and scale it; if the rig doesn't break it is a good rig.
Quite often, when we check the rig, we realize that we have forgotten to link a part of the rig or something doesn't deform properly on the mesh.
It is quite difficult to remember to check everything, so testing a rig is our only way of being sure is ready for production.
If you would like to build upon what you learnt in this article or if you would like to continue to follow this tutorial you can purchase the full eBook in the 3DTotal shop.
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