Archive for the ‘iridescence’ Category

In my last post on iridescence, I explained using the shellac shader, which is a physically correct way to create iridescence for animations. This example is how I create iridescence in things like oil spills, liquids, bubbles. This technique here is a non-physically correct method, but visually it looks correct…after all, isn’t 3D just smoke and mirrors anyway trying to simulate reality?

Iridescence shader on bubbles

To create the bubble material I use the tried and true Arch & Design Shader. The diffuse color is a non-issue here. The reflection is set to 1.0 (white), refraction is set to 0.95 with an IOR of 1.4.

The trick to this shader is the map in the reflection color slot. I use a swirl map. Initially, I set the base color to red, and the swirl color to green so I can see the swirl mix easily. Then when I got all of my swirl settings to look convincing, then I applied a gradient ramp map into into each the base and swirl slots. The idea was to create a rainbow spectrum, again, just using the colors red, green, and blue. For the base gradient ramp, I blended red to green. For the swirl gradient ramp, I blended green to blue. The end result of the swirl provides the whole mix with a rainbow type effect.

Finally to get the swirls to move around the bubbles, I just rotated the spheres, and keyed the rotation. This can also be achieved with a uvw map modifier with a animated gizmo to move the swirl around the sphere, but I opted for the rotation keying to give me variation among spheres.
Iridescence. We all know what it is, and never knew what it was called. Technically it is the physical effect of a color changing based on its viewing angle. We see this in CD’s, insects, bubbles, cars and so on. Here I’m going to explain how you can do this in 3DS Max.

Iridescence shader on torus knot

When I started thinking about the shader, I began to think of how iridescence works in reality. This effect happens due to objects having multiple layers with different reflections. So the shader that would work best for this would be a multi-layered shader. The one I used here was Shellac for the controlled layering. Essentially I created 3 A&D materials that were highly reflective and layered them. Each with different reflection colors, red, green, and blue. The real trick to getting that iridescent color is by rotating the anisotropic reflection in each shader with a different rotation amount. Just enough to blend the rgb values gives a believable rainbow spectrum.


But just how do you get that cd reflection to scatter from the center out? This is where the gradient ramp comes in. Choose a radial spread to get the right results. It’s placed in the bump map slot, and this is what scatters the reflection in a beliveable way. And as always you have to apply a UVW map onto your object so it knows where the radial gradient is starting from.

Happy texturing!


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