This page provides some details in the settings available when using the Scanned Material in V-Ray.
The BRDFScanned material allows the rendering of scanned BRDF material data stored in .vrscan files. These files are produced by Chaos Group's own internal material scanner and accompanying material creator software.
The BRDFScanned material requires a separate license to work correctly. Without a license, the material will not show its UI and will render with a watermark, otherwise, it should be able to render the sample scenes below.
The scanned material renders the captured appearance of an actual physical material sample, that has been scanned with special scanner hardware. The material goes beyond single-point BRDF capture and can faithfully represent the textured appearance of a large number of real-world surfaces using bidirectional texture function (BTF) approximation.
Because the scanned material simply reproduces the way a physical material responds to light, is has no notion of "diffuse" or "reflection" components, "normal" or "bump" maps.
Currently, the material can render only opaque surfaces. Also, for the moment except for some general tint control, the material is unmodifiable - i.e. you can't change glossiness, increase reflectivity etc. You can only change the overall tint of the material. In its present form, the material is targeted at users that need to match exactly a given real-world sample.
The .vrscan files tend to be quite large as they need to pack a lot of data (they need to describe the BRDF of the material over its entire surface).
UI Path: Asset Editor > Add Material > VRscan
File – The file name with the data for the scanned material; usually has a .vrscan extension.
Tiling Factor – Global multiplier for U and V coordinates.
Plain Material – A strategy used for material display. It controls the visibility of textures (if present). Possible values are:
Average BRDF – Averages the BRDF and removes any anistropy. This mode can be used on objects without proper UV coordinates.
Average isotropic BRDF – Averages the BRDF and can be used to speed up the rendering for previews. Because texture details are removed, this also removes any tiling artifacts that might arise if the scanned sample does not tile very well. UV coordinates are still needed because most BRDFs are slightly anisotrpic.
Color Space – Choose between sRGB, Adobe RGB, and Pro Photo color space models.
Two Sided – Enables both sides of the material.
Transparency – Turns on transparent properties of the material.
Trace Depth – Controls the number of reflection bounces. A value of -1 means that the reflection bounces are controlled by the global V-Ray trace depth in the Global switches rollout of the Renderer Settings.
Cutoff – A threshold used to speed up reflections. If the contribution of reflections falls below this threshold, the reflections are not traced. This is similar to the Cutoff threshold of the VRayMtl material.
The section displays some useful information contained in the .vrscan file, like the actual material sample size.
The Appearance parameters allow for further customization of the scanned material.
Filter – Enables the use of the color filter.
Filter Color – A color multiplier for the material sample and can be used to tint the material (it will affect the color of the reflections as well as a post effect).
Filter Strength – Multiplies the effect of the filter.
Paint – Enables the use of Paint Color.
Paint Color – Changes the color of the material without loosing the texture or change the reflection color. For example, changing the color of wood or leather without losing their textures.
Paint Strength – Multiplies the effect of the paint.
Gamma – Adjusts the gamma of the material (including paint color and filter color if used) as a post effect.
Saturation – Controls the saturation of the material (including paint color and filter color if used) as a post effect.
The clear coat parameters are similar to those found in the VRay Car Paint Material. These parameters are only available if while scanning an object, it is determined that the object possesses the properties of a material with a clear coat.
Reflection – Enables the tracing of a clear coat layer for the material's reflection.
Specular – Enables highlights from point light sources for the coat layer.
IOR – Determines the Index of Refraction of the coat layer and controls the strength of the reflections. A value of 1.0 does not produce any reflections and disables the coat layer. Higher values produce stronger clear coat reflections. The .vrscan file contains the correct value (typically 1.6) for this parameter, which is set automatically when the file is loaded but can be adjusted higher or lower if needed.
Bump Strength – The coat layer has a built-in bump map stored into the material sample file. This parameter allows control over the strength of that bump.
UV Channel/Set – Specifies the index of the mapping channel data to use. A value of -1 will take the first available channel.
Repeat U/V – Determines how many times the scanned material will be repeated in the 0 to 1 UV square.
Offset U/V – Controls the offset in the U and V direction.
Rotate – Rotates the material(in degrees).
Tile U/V – Tiles the material in the U and V direction. If the option is disabled, the Default color will be used outside the 0 to 1 UV square.
Mirror U/V – Mirrors the material in the U and V direction separately. The option will cut the material in half flipping one side vertically or horizontally. This can be used to avoid seams in-between non-tileable repeated textures/materials.
Double-sided – Enables both sides of the object to be affected by the UVW data.
Can be Overridden – When disabled, the material is not overridden by the Material Override option in the Render Settings.
VRscan material is not yet supported in GPU render mode.