Car Rigging

Rigging the car without skinning can be a very fun and fast process if you know what and how to do. But if you don't it cant become frustrating very quickly, especially on the turning wheels.

In previous post we covered almost all our weapons. In this post I want to talk about two more. Very simple and lightning fast methods to connect attributes of different objects. And also how to lock and unlock attributes.

1. Hiding Attributes.

Simply select Attributes that you want to hide (so animator would not mess up your work) and Rclick -> Lock or Lock and Hide Selected.

But make sure that object was frozen before you hid the att. Because to freeze transformation you will have to get those attributes back and unlock them.

to do that go to Window->Genereal Editors-> Channel Control and move att back.

2. Connection Editor.

You select two object which attributes you want to connect and go to
Window->General Editors->Connection Editor
Here you can link any attribute of one object to any attribute of another, it's like SDKs but much faster and unlimited.

And a bit about limiting attributes, you can do that in Attribute Editor, under Limit information in Translate,Rotate or Scale relatively.

3. Expressions.

The most reliable thing in my opinion. I had so much trouble because I started using constraint on the front wheels and they messed up something in there. After breaking connection on the att (Rclick->break connection) constraint nodes stay in the outliner, so you need to delete them by hand, I didn't know that and had so many different hidden constraint in there no wonder wheel did this.

Maybe that was not the only reason why that happened. It is very important to keep your model clean, sometimes undergroups can be all clean, frozen, but the main group have some numbers. Amd who knows if it can affect your undergroups. Tu fix this issue I had to do some major cleaning, bringing back all the attributes to freeze transformation of the main wheel group, deleting all the constraints, checking everything 100 times. Then I decided to go 100% expression mode. Because they are fast, clean, and don't leave any nasty stuff after deleted.

to make expression you go to Window->Animation Editors->Expression Editor

You write expressions in the object that you want to control, not in the controller. But you will need controllers name.

So you select your controller,then att that will be controlling, in Selected object line you will get the name, copy it. Now go to your object, select the att that going to be controlled, paste into expression window what you copied from the controller, now copy Selected object and Attribute line and paste it before controllers name, hit space = and space again. So my expression for hood looks like that, notice that hood is selected, not the controller.

So rotation of the hood group on X axis is controlled by translation of the controller on Y axis.

What is *-25 you would ask, well that is the most awesome thing about it. Unlike connection of the attributes where you get 1 to 1 motion, in expressions you can multiply the effect if its not enough or divide it if its too much. You also can invert the motion by adding -. I used expressions for everything apart from mirrors and steering wheel (turn of wheels is controlled by expression). On them I used orient constraints, just for variation.

4.Combining curves.

One last thing, very useful. To create nice looking controllers you will need to combine curves sometimes. And for some mysterious reason Maya can't simply combine them, you can combine meshes but not curves, sometimes software makes you angry when simple things are made more complicated than they should be. It is still simple,but takes more time to do.

You create your curves,freeze transformation (this is very important, otherwise it will not work), then create a group in outliner (empty one), name it how you want your controller to be named e.g. Hood_ctrl, then in outliner go Display->Show Shapes. now open little groups of your curves and select shapes directly, select your empty group last. Now go to MEL and type   parent -r -s
Go to Display and turn off show shapes. Now you have your nice combined curve.

This was a long journey, but I liked it, though sometimes it tortured me. Learned many new things while creating these rigs.

The End.