Render magic, whatever your toolset

Lee Griggs

In-house artist at Autodesk

Some CG techniques are obvious, like rendering a polygonal mesh with a traditional surface shader. But Lee Griggs, technical artist and industry expert, doesn’t settle for obvious looks. He uses CG tools – and Arnold in particular – to do things we’ve never seen before. Click through to learn more about the tools and techniques behind Lee’s innovative workflows and download your free Standard Volume shader file.

Some CG techniques are obvious, but Lee Griggs, technical artist and industry expert, doesn’t settle for obvious looks. He uses CG tools and Arnold to do things we’ve never seen before. Click through to learn more about the techniques behind Lee’s innovative workflows.

Under the hood / Step 01

I want to let other artists know about Volume Displacement and have an opportunity to experiment with its many creative uses, which even I am only just beginning to explore. You can use it in all the supported 3D DCC tools including Maya, 3ds Max, Cinema4D, Houdini and Katana.

I’d like to walk you through how I created this image using the Volume Displacement technique; with Maya and Arnold. The image started as a VDB file that I had previously created. I started by cranking the density until the image looked like geometry. The effect gives the volume an abstract yet realistic look.

I’d like to walk through how I created this image using the Volume Displacement technique; with Maya and Arnold. The image started as a VDB file that I had previously created. I started by cranking the density until the image looked like geometry. The effect gives the volume an abstract yet realistic look.

Under the hood / Step 02

I really wanted to make the texture pop, so I projected an organic-looking texture map through the camera, using a Camera Projection node. I have a library of texture maps that keeps growing, and organic texture sources are some of my favorites as they help break out of traditional CG looks.

I then added Depth of Field to hide some of the projection effect—which initially looked a bit strange but I kept experimenting until I had something I liked. For me, it’s all about experimentation with different textures and projections. My advice is to try them all.

I wanted the texture to pop, so I projected an organic-looking texture map through the camera, using a Camera Projection node.

I then added Depth of Field to hide some of the projection effect—which initially looked a bit strange. For me, it’s all about experimentation with different textures and projections. My advice is to try them all.

Under the hood / Step 03

I really like how I was able to get the wispy tendrils to fade off. I used a Range Shader to remap the input values of the original texture to displace the volume shading effect, which added contrast and created the gaps and holes in the volume. The Range Shader can often come in handy for manipulating textures to get different and unexpected results. The final image used an Output Max value of 4. It just gave it more of a solid object feeling—almost like coral.

I really like how the wispy tendrils fade off. I used a Range Shader to remap the input values of the original texture to displace the volume shading effect, which added contrast and created the gaps and holes in the volume. The final image used an Output Max value of 4. It gave it more of a solid object feeling—like coral.

Under the hood / Step 04

I used the Scatter and Transparent Colors settings in the Standard Volume Shader to control the colors. Scatter is the brightness of the volume under illumination. It’s the ratio of light that is scattered rather than absorbed.

In terms of lighting, I wanted to give the image some backlighting that would show through the edges. I added a single HDRI light source in the background and adjusted the Transparent Color setting to let the light bleed through.

I used the Scatter and Transparent Colors settings in the Standard Volume Shader to control the colors. Scatter is the brightness of the volume under illumination. It’s the ratio of light that is scattered rather than absorbed. To give the image some backlighting that would show through the edges, I added a single HDRI light source in the background and adjusted the Transparent Color setting.

Under the hood / Step 05

Volume Ray Depth allows you to configure settings that limit the ray recursion based on ray type and can help you create dramatic differences to a scene or image. Increasing the Volume Ray Depth allowed me to add multiple scattering bounces within the volume. This gave me the desired length, but increased render times. Fortunately, the test rendering in the interactive Arnold RenderView is remarkably fast. Overall, it was worth it, as the volumes look more believable and I could get closer to the final result saved a lot of time downstream during compositing and creative finishing.

Increasing the Volume Ray Depth allowed me to add multiple scattering bounces within the volume. This gave me the desired length, but increased render times. Fortunately, the test rendering in the interactive Arnold RenderView is remarkably fast. Overall, it was worth it, as the volumes look believable and I got closer to the final result, saving a lot of time downstream during compositing and creative finishing.

Under the hood / Step 06

I’m a huge fan of experimentation—especially when it comes to what I can do with the Arnold renderer. While I’m most comfortable working in Maya, the Volume Displacement technique can be used in the other Arnold supported applications as well.

To try the Volume Displacement technique in Maya, download my free Volume Shader file.

I’m a huge fan of experimentation—especially when it comes to what I can do with the Arnold renderer. While I’m most comfortable working in Maya, the Volume Displacement technique can be used in the other Arnold supported applications as well.

To try the Volume Displacement technique in Maya, download my free Volume Shader file.