Turnip Shading

My Shader Programming class at BYU introduced shading as a layer-by-layer process that slowly adds more detail to the shader until you have an interesting surface with lots of depth to it. Our first project was all about recreating something that already exists. In this case, a piece of produce. I didn't want to be one of a half dozen students working on an apple, so I chose a turnip instead.

Our first deliverable wasn't actually a shader at all - it was a hand drawn exploration of the produce we chose. Layer by layer we were supposed to paint our fruit until we had the finished product so we could start to get a feel for the layering process. If it was a different color or a different pattern, it went on a new layer. Only five of the steps are shown in the progression above, but the full exploration had thirteen different layers to get to the final image.

From there, a simple turnip was modeled in Autodesk Maya and imported to Houdini to start the shading process. Everything on this turnip was procedurally generated using Houdini's node networks, so all the spots, wrinkles, and bruises had to be shaped with noise and other patterns, not painted on.

Using a material builder and various VOP nodes inside, layers of color and detail were built up to mimic the real turnip I had sitting on the desk next to me as I worked. In order, we have the base layers of cream and purple, some darker purple spots and bruising, some fine speckles of dust and the stem coloring, the tiny lines you find on the skin of most root vegetables, and some more dust along with the displacement. Mimicking the coloring and patterns wasn't enough on its own - even if the surface looked like a turnip, the highlights on the skin still wouldn't have been right if I didn't add in some texture with displacement.

Our final deliverables were a 360 degree turnaround and a composition, as well as the full Houdini file so our shader networks could be evaluated. This was a fun project that taught me a lot about shading and how to use Houdini's tools, and I was able to use the things I learned here on several projects in the future, such as the Gingerbread project senior year.