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The MtlWrapper node provides inputs for controlling various material properties. Some correspond to parameters in the section below.

base_material

 – Specifies the material that the additional wrapper properties

are applied to.

Generated GI Mult.

 – A multiplier for the amount GI generated by the material.

Receive GI Mult.

 – A multiplier for the amount GI received by the material.

Generated Caustics Mult.

 – A multiplier for the amount of caustics generated by the material.

Received Caustics Mult.

 – A multiplier for the amount of caustics received by the material.

Subdivs Mult.

 – A multiplier for the subdivisions of all secondary ray tracing done for the particular surface.

Use Irradiance Map – When enabled, the Irradiance Map

is used to approximate diffuse indirect illumination for the material. When disabled, brute force GI

is used. Can be used

for objects in the scene which have small details and are not approximated very well by the Irradiance Map.

– Determines the appearance of the object in the alpha channel of the rendered image. A value

of 1.0

 means the alpha channel

is derived from the transparency of the base material. A value

of 0.0

 means the object

does not appear in the alpha channel at all and

shows the alpha of the objects behind it. A value

of -1.0

 means that the transparency of the base material

cuts out from the alpha of the objects behind. Matte objects are typically given an alpha contribution

of -1.0. Note that this option is independent of the Matte surface option (i.e. a surface can have an alpha contribution

of -1.0

 without being a matte surface).

Generate Render Elements

 – When enabled, V-Ray

generates zDepth, velocity, extra tex and multi matte render element for matte objects. When

disabled, V-Ray

does not generate any render elements for matte objects.

Matte Surface – Makes the material appear as a matte material, which shows the background, instead of the base material, when viewed directly. Note that the base material is still used for things like GI, caustics, reflections, etc.

Shadows – When enabled, makes shadow visible on the matte surface.

Affect Alpha – When enabled, makes shadows affect the alpha contribution of the matte surface. Areas in perfect shadow

produce white alpha, while completely unoccluded areas

produce black alpha.

Shadow Tint 

 – An optional tint for the shadows on the matte surface.

Shadow Brightness – An optional brightness parameter for the shadows on the matte surface. A value

of 0.0

 makes the shadows completely invisible, while a value

of 1.0

 shows the full shadows.

Reflection Amount – Shows the reflections from the base material.

Refraction Amount – Shows the refractions from the base material.

GI Amount – Determines the amount of GI shadows.

No GI On Other Mattes – Causes the object to appear as a matte object in reflections, refractions, GI, etc. for other matte objects. Note that if

the option is on, refractions for the matte object might not be calculated (the object will appear a matte object to itself and will not be able to "see" the refractions on the other side).

Matte For Secondary Rays – Normally the base material

is used when an object with a MtlWrapper is seen through reflections/refractions. This option controls whether the MtlWrapper shows the base material or environment when seen through secondary rays (e.g. reflections/refractions).

Disable

 – The base material

is used when the MtlWrapper is seen through reflections/refractions.
Without Projection Mapping – The environment

is seen through reflections/refractions.
With Projection Mapping

 – The environment

is seen through

reflections/refractions with projection mapping to increase the realism.

 – This number can be used to prevent the blending of light cache samples across different surfaces. If two objects have different GI surface IDs, the light cache samples of the two objects

is not

blended. This can be useful to prevent light leaks between objects of vastly different illumination.

Trace Depth

 – Specifies the number of times a ray can be reflected. Scenes with lots of reflective and refractive surfaces may require higher values to look correct. A value

of -1

 specifies that this option is controlled by the

global Render Settings.