This page provides information about the Blend material in V-Ray for Rhino.
Overview
The V-Ray Blend Material can be used to layer several V-Ray compatible materials in an efficient manner. It can be used to create complex materials like car paints, human skin (when used with the V-Ray Subsurface Scattering Material as a base material) etc.
V-Ray Blend Material takes a base material and applies other materials (coatings) on top of it. This works like a stack, where each coat material blends between its own shading and that of the materials below it in the stack.
UI Paths
||V-Ray Asset Editor|| > Materials (right-click) > Blend
||V-Ray Asset Editor|| > Create Asset (left-click) > Materials > Blend
UI Options
The Blend material settings are organized in Basic and Advanced modes. You can switch the mode from the toggle button under the Preview Swatch or globally from the Configuration rollout of the Settings tab.
From the Add Attribute button, you can select additional attributes that can add up to the appearance of the material. For more information, see the Attributes section.
A Reset option is provided in the context menu of each Color Slot. You can reset the color to the default one.
Base
Add Coat – Adds another Coat layer to the stack.
Base Material – Allows the user to select the base layer material to which the bump/normal effect is added. This slot can be empty in case a transparent base is needed.
Additive Mode – When enabled, causes the V-Ray Blend Material to behave like a multi-layered Shellac material. Note that this would often result in a physically incorrect material (e.g. a material that reflects more light than falls on it). It is not recommended to use this option unless you know what you are doing.
Coat
Enables/ disables the layer in the stack. Note that this is the layer you add vie the Add Layer button.
Material – Specifies the coat layer material.
Blend – Specifies how much of the final result is contributed by the corresponding coating material, and the rest of the materials below it. If the Blend amount is white, the final result is comprised of the coat material only, and other materials below it are blocked. If the Blend amount is black, a coat material has no effect on the final result. This parameter can also be controlled by a texture map.
Blend Tex Mult – Specifies a multiplier for the amount that the texture is blended with the Blend color.
Binding
Texture – Selected Bitmap texture is displayed in the viewport and it overrides all other material parameters. The viewport texture does not affect the way the material is rendered with V-Ray. It is mainly used for preview purposes.
Keep in mind that procedural textures are not shown in the viewport, however, any Bitmap textures, including ones nested in procedurals, will be automatically displayed.
Override Control
Can be Overridden – When enabled, the material can be overridden by the Material Override option in the Settings.
Attributes
The attributes from the following expandable menus are available for the Blend material.
Bump
Mode/Map – Specifies the bump map type.
Bump Map – A height map should be used.
Bump Texture Channel – Some V-Ray textures have a special bump channel output that can be used here. It is most commonly used for Round Edges effect. Edges texture is used as a bump.
Normal Map – RGB normal map should be used with this option. Note that in most cases the normal map bitmap color space should be set to Linear to ensure correct results.
Amount – Multiplier for the bump/normal map.
Delta Scale – Specifies a scale for sampling the bitmap when using bump mapping. The exact value is calculated automatically by V-Ray, but can be caled here.
Outline
The Outline attribute is available only when the engine is set to CPU. It is currently not supported for GPU.
Line Color – Specifies the color of the outlines.
Opacity – Specifies the opacity of the outlines.
Normal Threshold – Determines when lines will be created for parts of the same object with varying surface normals (e.g. at the inside edges of a box). A value of 0.0 means that only 90 degrees or larger angles generate internal lines. Higher values mean that smoother transitions between face normals can also generate a line. Setting this value to 1.0 fills curved objects completely.
Overlap Threshold – Determines when outlines will be created for overlapping parts of the one and the same object . Lower values reduce the internal overlapping lines, while higher values produce more overlap lines. Setting this value to 1.0 fills curved objects completely.
Width – Specifies the width of the outlines.
Inner Line Control – Enables a separate control for the inner edges.
Inner Line Color – Specifies the color of the inner lines
Inner Width – Specifies the width of the inner lines.
Some of the global parameters have an effect on all materials with Outline attribute. These parameters are Width Type, Trace Bias, No Inner Edges, Visible in Secondary, and Compensate EV.
Displacement
This is a legacy attribute that will be removed in the future. Consider using the geometry displacement modifier instead. It can be created as a geometry asset in the Outliner and can be applied to objects in the scene. Note that the displacement effect will no longer appear in the Preview Swatch.
Displacement – Enables or disables the displacement effect.
Mode/ Map – Specifies the mode in which the displacement is rendered.
2D Displacement – Bases the displacement on a texture map that is known in advanced. The displaced surface is rendered as a warped height-field based on that texture map. The actual raytracing of the displaced surface is done in texture space and the result is mapped back into 3D space. The advantage of this method is that it preserves all details in the displacement map. However, it requires the object to have valid texture coordinates. You cannot use this method for 3d procedural textures or other textures that use object or world coordinates. The parameter can take any values.
Normal Displacement – Takes the original surface geometry and subdivides its triangles into smaller sub-triangles, which then are displaced.
Amount – The amount of displacement. A value of 0.0 means the object appears unchanged. Higher values produce a greater displacement effect. This parameter can also take a negative value, in which case the displacement pushes geometry inside the object.
Shift – Specifies a constant, which is added to the displacement map values, effectively shifting the displaced surface up and down along the normals. This can be either positive or negative.
Keep Continuity – When enabled, tries to produce a connected surface, without splits, when there are faces from different smoothing groups and/or material IDs. Note that using material IDs is not a very good way to combine displacement maps since V-Ray cannot always guarantee the surface continuity. Use other methods (vertex colors, masks etc.) to blend different displacement maps.
Resolution – This option is available when the Mode/Map is 2D Displacement. It determines the resolution of the displacement texture used by V-Ray. If the texture is a bitmap, it is recommended to match this resolution to the size of the bitmap. For procedural 2D maps, the resolution is determined by the desired quality and detail in the displacement. Note that V-Ray also automatically generates a normal map based on the displacement map in order to compensate for details not captured by the actual displaced surface.
View Dependent – When enabled, Edge length determines the maximum length of a subtriangle edge in pixels. A value of 1.0 means that the longest edge of each subtriangle is about one pixel long when projected on the screen. When disabled, Edge length is the maximum sub-triangle edge length in world units.
Edge Length – Determines the quality of the displacement. Each triangle of the original mesh is subdivided into a number of subtriangles. More subtriangles mean more detail in the displacement, slower rendering times and more RAM usage. Less subtriangles mean less detail, faster rendering and less RAM. The meaning of Edge length depends on the View dependent parameter. The slider's minimum range is set to 0.4. Using lower values is still possible by manually typing them in the input box but it may cause significant render delay.
Max Subdivs – Controls the maximum sub-triangles generated from any triangle of the original mesh when displacement is enabled. The value is in fact the square root of the maximum number of subtriangles. For example, a value of 256 means that at most 256 x 256 = 65536 subtriangles will be generated for any given original triangle. It is not a good idea to keep this value very high. If you need to use higher values, it will be better to tessellate the original mesh itself into smaller triangles instead. The actual subdivisions for a triangle are rounded up to the nearest power of two (this makes it easier to avoid gaps because of different tessellation on neighboring triangles).
Water Level – Clips the surface geometry in places where the displacement map value is below the specified threshold. This can be used for clip mapping a displacement map value below which geometry will be clipped.
Level Height – Value below which the geometry is clipped.
Materials need to be applied to objects (groups/components) to have working displacement. If various materials are applied to different faces of an object, the displacement from the top-level (group/component) material will be used on all of them. Normal Displacement will take into account the texture size of each different face material, while 2D Displacement will ignore them.
Raytrace Properties
Visible to Camera – When enabled, makes objects using this material visible to the camera.
Visible to Reflections – When enabled, this option makes objects using this material visible for to Reflection rays.
Visible to Refractions – When enabled, this option makes objects using this material visible for the Refraction rays.
Cast Shadows – When disabled, all objects with this material applied do not cast shadows.
Override
Shadows – The material that is used when a shadow ray hits the surface.
Reflection – The material that is used when a reflection ray hits the surface.
Refraction– The material that is used when a refraction ray hits the surface.
GI – The material that is used when a GI ray hits the surface.
Environment – The texture that will be used instead of the scene environment maps.
Material ID
ID Number – Isolates objects as an R/G/B mask in the MultiMatte render elements.
ID Color – Allows you to specify a color to represent this material in the Material ID VFB render element.
Each material is assigned with an automatically generated ID Color.
Notes
- The 2D mapping (landscape) method only supports one UV mapping channel.