Easter Project 05

A couple of final new things I learnt about while making this rig.

On problem I have always found a pain in 3D is that the IK legs pop over when the controller at the ankle passes the hight of the pole vector (the origin of the IK set up that dictates the direction for the knee to point generally located at or around the pelvis). There is such a simple solution to this I can't believe it not used more often. Here is a comparison between the standard IK set up and my non flip IK leg.

Another thing I learnt about was the advantages of having an extra joint at the elbow or knee.

See in these examples (screen captures from the DVD I have been referencing - Rigging for Feature Animation from Fahrenheit Digital) how having a single joint is fine for a 90 degree bend but you get an ugly overlap in the mesh when you bend the limb further.

In the past I have gotten around this with the weights on the mesh (determining how the mesh is influenced by the bones), but this way makes much more sense.

You don't have to animate the extra little joint, it is set up to inherit rotation from the for arm, so to animate its no different that a two bone joint. I have always tried to avoid IK control for a 3 joint limb, but I have learnt that as long as you keep your local rotation axis lined up through the length of the limb (something I hadn't even considered before) then they work just fine.


******************************************

I'm not sure how much of this I'm going to be able to cover in class because of the time constraints (really we only get about 160 class hours devoted to just 3D and I think I already try to squeeze in to much) so make sure you ask me if there is anything here you want to learn more about and maybe we can get together outside of class time at some stage and talk about it. Also any ex students who want to know more about any of these things can leave a post on the Forum and I'll do my best to help you out.

Easter Project 04

Couple more things I wanted to show about my new rig. First up comes the stretchy IK arms for "cartoony" stretch (to be used sparingly). There's a lot of maths involved in getting this to work. Dividing the current distance between the shoulder and IK controller by the standard distance between the shoulder and controller and then multiplying the length of each arm bone by the result. Confused? Don't stress, if its something you want to know more about I can show you in class.

Next up is the stretchy spline spine, you can position the chest or pelvis as you wish and the bones between adjust to suit. I did learn an even better way to achieve using a strip of polygons with hair follicles mounted on them (waaa!). I didn't use it here though because the EDU copy of Maya doesn't come with the hair plug in and I want this rig to work on the PCs at tafe.

Easter Project 03

One of the biggest new things I wanted to do for this rig was come up with something that had arms you could easily switch between IK and FK. Here is a slow transition between the two.

You can see that there are actually three arms, the FK bones, the IK Bones and the TRUE Bones. The mesh or skin is bound to the True Bones but you never actually animate them. They are constrained to the IK and FK bones in a way that can be switched or even animated. When the switch is set to 0 the TRUE Bones line up with the IK Bones, when the switch is set to 10 the TRUE Bones line up with the FK Bones. In this example I set a key on frame one with the switch set to ten and the FK Bones down by the characters side, then I set a key on frame 80 with the switch set to zero.

You can see that as the switch inbetweens between the FK and IK the TRUE arm starts to move away from the FK bones and then aligns its self with the IK bones. I connected the switch to the visibility on the IK and FK bones as well so that the FK bones automatically disappear as the switch changes over and the IK bones automatically appear.

NOTE: I didn't use the IK/FK switch system from the DVD it required that you use a supplied script that I wanted to avoid. I used the tutorial from the Rigging101 web site.

Easter Project 02

I have been setting up some hand controls for the rig, the dials on the right of screen control the position of the fingers. For the new folks, it can be a pain picking out the little finger bones so these controls are designed to help, you can pick individual joints or all the fingers at once to curl the whole hand up into a fist.

In this example I only rotated the bones on one axis, but they are connected on all three. You can rotate the joints in any direction.

Easter Project 01

For Christmas I got a DVD about rigging in Maya, for the newer kids, rigging is the setting up and structuring of your characters skeleton. The skeleton bones and controllers are the tools you use to manipulate and pose your 3D character. Ever since then I have been plugging away at a rig in my spare time. Why? Well I think its important for those of you with high end 3D (film and TV) aspirations to be able to have a go at animating with a professional standard rig. The problem is that in the limited time you have to work with 3D in our course there's no way most of you could explore rigging in enough depth to build a skeleton like this.

I'm giving this one to the Tafe so you can all have a play with it. In fact as long as you prove to me that you understand and can apply basic rigging techniques, then you can use this rig to bind your character too (if you want). Here is the first piece of test animation I've made with the rig, the animation is nothing that fancy (an afternoons work), but you can see that the rig has stretchy limbs, and the arms can switch between FK and IK*.

* FK is forward kinematics which means controlled from the shoulder down, IK is inverse Kinematics which is when you control an arm (ar any limb) from the other end (the wrist in this case). Each set up has its own strengths and weaknesses, so its good if your rig can switch between the two.