GNOMON MAYA MENTAL RAY ISO

1. RAY TRACED SHADOWS

Ray traced shadows are visible in reflections and refractions and can be traced through volumes such as

fluids, particles, etc. Ray traced shadows also allow for shadow attenuation, which means the shadows

are harder near the surface casting them. In normal circumstances, when using ray traced shadows you

should use the simple flag within the render globals. If you need to trace a ray through a volume (like

cloud particles, fluids, or volume primitives) set the shadow options to segments.

2. DEPTH MAPPED SHADOWS

Depth mapped shadows differ from ray traced shadows in that they are not visible in reflections or refractions,

do not have attenuation, and do not trace through volumes. Depth mapped shadows can render

very quickly and are able to produce washy soft shadows at a fraction of the render time required to render

the same effect with ray traced shadows. The trick to creating depth mapped shadows is balancing

your resolution to softness: the softer the shadows, the less resolution you need.

3. SHADOWS WITH FUR

Shadows give fur depth and fullness. No special setup is required, and though you can use either ray

tracing or depth maps, depth map shadows with the lowest possible resolution give you the best performance.

Furthermore, use samples that produce predictable results and remember that when rendering

fur you will need to use higher anti-aliasing samples, like 1 and 3.

4. VOLUMETRIC SHADOWS

You can cast volumetric shadows using either spot lights or point lights, and either depth mapped or ray

traced shadows. When using a spotlight, adjust the quality of your shadows by turning on volume sampling

on the cone primitive. You may need to use values between 50 and 70 to achieve your optimum result.

5. AREA LIGHTS

Use area lights to create soft lighting effects. Use the area lights you find under the Mental Ray tab of either

your spot or point light. These lights can be various shapes or volumes and can be scaled and placed.

Turn up the sampling value on your area lights to control quality. Remember that ray tracing does not

require that you adjust the angles of your lights or soften your shadows, as they will soften when you

scale your light. You will, however, still need to adjust the quality of your shadow.

6. BLURRY REFLECTIONS AND REFRACTIONS

You can create blurry reflections and refractions with Maya shaders using the Mental Ray tab within your

shader, where you can adjust the blurriness and sampling values.

7. CONTOUR RENDERING

Contour rendering can be used to render outlines around various features of your scene, including objects,

materials, normals, depth, contrast, etc. Contour thickness is adjusted per material, accessed within the

render globals under the contour rendering tab. You can create very versatile cartoon shaders by combining

multiple renderings of contours and ramp shaders.

8. HIGH DYNAMIC RANGE IMAGES

High Dynamic Range Images (HDRI) contain multiple levels of exposure within a single file. You can adjust

the image’s brightness and contrast of the image by using the color gain on the image file node. Because

HDR images represent the image’s exposure level extremes, they are great to use as reflection maps.