Chickadee

Chickadee

I've heard that feathers are the hardest thing to create in grooming, so I decided to take on this challenge during my final year of college.

The software I used is Houdini and these are the plugins I used for the process: The feather tool for Houdini by Tighe Rzankowski, and Groombear tool by kwac.

This bird was created as one of the characters in my thesis film Nirvana.  Here are some footages from the film. I am responsible for all simulations (feather, hair, soft body), grooming, and shading.

Here are some final renders from Houdini using Redshift.

Grooming and Feather Breakdown

Wing Feather Deform

I decided to deform the wing feather with the rig. Luckily, the feather tool has a feather deform node based on the name attribute. I simply had to transfer back the name attribute to the cached animation from Maya.

Simulations

I used vellum for the soft body sim. First I tried to use the vellum tetrahedral soft body shelf tool for the sim. However, since I only wanted to simulate the belly and pin constraint the rest of the body back to the animation, I had trouble pinning and painting attributes for the constraint points inside the body. Based on Entagma's soft body simulation using grain, I decided to use both grain and cloth and constraint them together using connected adjacent pieces to recreate my tetrahedral mesh. I was able to transfer the attributes I painted on the skin to the grains inside the body and pinned the points inside the body to create a more stable simulation.

I separated the feathers around the wing area and the rest of the body. The wing area I used point deform to warp the geo onto the body and let it deform with the animation. The rest of the body feather I used a proxy geo for sim using vellum cloth and used that to deform my feathers post-simulation. Thanks to the demo file Tighe provided in the feather tool demo, I already had a foundation for the set up. A ramp for the pin constraint stiffness drop off from root to tip was created using uv. I also painted a map and multiplied them together to give different areas of the body more or less stiffness. The trickiest part was the area between the body and the wing. The feather detangle tool Tighe created was great for the rounded part of the mesh, like the belly, but couldn't fix the intersecting mesh around the root of the wing. I couldn't think of a way to detangle them and I was out of time to place the feathers in those areas by hand. So I manually deleted the popping feathers after the simulation. 

The feather on the head I simulated using vellum hair and used the body feather sim as a collider.

Shading

For the color of the body feathers, I wanted to mix the body texture base color with the feather color. So I imported the texture and baked the color onto the point Cd attribute. I renamed the Feather Cd attribute to FeatherCd, and v@Cd *= v@FeatherCd*chf("muti"); to multiply the two colors with a float number as bias. 

Responsible for Grooming, Shading & Simulations. 

Model and texture: Shuqi Chen; Rigging: Kyra Procopi; Animation: Sarita Lam

Special Thanks to: Natalie Homewood, David Barksdale & Mikki Rose