Material. Vray For Rhino

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r18 - 14 Nov 2006 - 11:55:19 - MichaelMehnert

Materials
Introduction
The material editor can be open per Rhino3D menu "Vray" -> "Material Editor". Per right mouse button (RMB) click on the "Scene Materials" materials can be imported, added new or purged unused materials. A material can based on four layertypes - emissive, reflection, diffuse and refraction. A layer type can contain unlimited layers. All layers are in order like placed on the material from top to down. The default material contain one acitve diffuse layer. Additional layers can be placed per RMB click on a layer type. The preview window dosn't show the current selected material, it show the last rendered preview. All examplerenderings are done in full adaptive mode and noisethreshold 0.02 (good preview quality).
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Screenshot of the VfR material editor:

If the user like to see the difference between two material settings per preview, than the prepass of the preview window should be disabled per RMB at the preview window. l Extra controls of the preview window:

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Diffuse material
Simple to create and fast to calculate - the diffuse material. It looks like loot (Plasticine®) or a dull plastic. The color can be set per Rhino color chooser or texture editor. The edito will open per mouse click on the little "m". Textures are using the map channels of the McNeel ? mapping tool (RCM).
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Singlediffuse layer material:

Shiny plastic or Ceramic material

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If we add a reflection layer and set the reflection map type to "fresnel", than we get shiny material like shiny plastic or Ceramic. The IOR is a material specific parameter and can be find for example at this list here (linkwanted). The refraction parameter can be ignored here, it is a current interface issue. A basic rule for shiny plastic is, that the reflections are not tinted by the material color. * Fresnel control of the reflective layer:

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Shiny plastic material:

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Wood material
Wood is a kind oftextured plastic material. Sounds strange, but anything are bits and bytes only in the CG world. Take a texture at the diffuse layer, set reflection at fresnel and set a reflection glossiness like necessary - 1 for clear finish or less for waxed wood. l Wood material options:

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Woodmaterial (reflection intensity boosted by double reflection layers - see "Tricks" at the end) :

Rubber material
The standard diffuse material looks dull, but for Rubber it should not be used. Rubber show very blurry speculars and so it is better to use the shiny plastic material with blurry reflections. Here an example with glossiness 0.5. l Rubber material:http://www.asgvis.com/VfRtw/bin/view/VfR/TutorialM

2006-11-15

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Rough material
Often used for Rough materials is a special render model based on the theory of Oren-Nayar. Typical examples of rough surfaces are the moon, felt, cloth, clay ... . All this materials seems to show a light distribution particular independent from the direction of the light. Extrem samples of thismaterials are looking flat, sometimes like textured emitters without self shadowing. At the moment Vray dosn't support an Oren-Nayar shader, but it can be good simulated (not faked!) by a single reflection layer (no fresnel) with a very low glossiness of 0.1. A side effect is, that the material color will be show much darker as in the Rhino color chooser (this is right - more infos at this forum...