The original model had been rigged for use within 3ds Max for another animation, but a new rig had to be built for it to work within Unreal. I was planning to base the scripting off of the Scorpion, so I studied how the rig for this vehicle was made before anything else. I didn't know at the time that I would be recreating this rig from scratch several times in the future, but the first version was made by mimicking the Scorpion's setup. Unfortunately, it was build backwards.
The second version sported bones that pointed the right way. Since the rig was the same as the Scorpion's, I was able to test out my rig by using it's animation tree. But that only showed me that though the bones were correct directionally, they were now misaligned rotationally. This resulted in the Durango doing fancy tricks, none of which were even remotely what I was looking for.
Rig number three was the most stable, and also veered away from the safety of copying the Scorpion. This was a custom rig, and only had as many bones as needed. A custom animation tree was created, and the car was able to idle.
Now that the rig was working, I could move on to physics. This ironically would result in more changes to the rig as I began learning about how Unreal handled hierarchies. To begin with, my rig had a single bone that all but the tires were children of. Because of this, physics were only applied to one tire instead of the entire vehicle. Unreal needed a single parent bone that all other bones in the system were a child of, and once this was discovered, the car would drop realistically without the tires bouncing off where ever they pleased.
I also set up the suspension at this point. This is done simply by importing the car with the suspension dropped as far as it can realistically reach, and then telling Unreal what the maximum distance upward on the Z axis each tire can go. A small hitch in this process came up as I discovered that the tire bones where once again not rotated the way Unreal wanted them, but a quick adjustment and re-import later and the suspension was working.
