Here is episode 6, a full humanoid robot!
Design and Concept
For this week I wanted to build a full robot. The goal was to model, rig and animate a full robot in a couple of days.
The design phase was pretty fun for this bot. I wanted something fairly boxy with a strong silhouette. Here is the original concept:
Model and Rig
Lately I've been combining the rigging and modeling process. I find this allows me to answer design questions and pose the character very early in the process.
The most challenging part of this rig was the legs. There were two main problems I had to solve. First was the three chain reverse ankle IK. The second was the rotation of the hip bone.
Three chain reverse IK
While I have built these before I always find them fun and challenging to make. First I had to ensure all the pivots were working correctly. I then had to build the pole vector parent mechanic. For this I built a small constraint set up using a bone that always stays in the middle of the hip and the foot.
This bone requires two more bones as well, one that parents to the hip and one that parents to the foot. The axis of these bones must match the middle bone. The middle bone is then damp tracked to the foot.
Lastly I parent the pole vector to this bone. This puts the pole vector in a great location (for the most part).
Here is an simple example of the functionality.
Hip Pivot IK issue.
For the hip pivot the main problem was in the design. There was a secondary pivot that had to work with the IK structure. I tried a couple of different techniques for this and I found that making the IK chain 4 bones long and adjusting the locking mechanics was the best solution.
To learn more about my modeling and rigging process watch the making of below.
For the animation I wanted to keep it fairly simple. I wanted the bot to take a step forward, grab the gun and shoot the gun.
In the future I want to spend more time on the vfx, although I'm still trying to work out how the vfx will look with this style. The Lego movies seem to have a pretty good handle of cartoony VFX. I'll probably use them as reference in the future.
Composition and Render
The compositing was fairly straight forward. The focus was on bringing color back into the image and to use the lights in the scene as compositional elements. I also tried a duel tone technique for the shadows but I decided against this.
The render was about 3 minutes a frame, the composition pass was about 40 second seconds.
Let me know if you have and questions I. The comments below!