This page provides some details in the settings available when using the Scanned Material in V-Ray.
Overview
The V-Ray Scanned 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 V-Ray Scanned Material material requires a separate license to work correctly. Without a license, the material will not show its UI and will render with a watermark.
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, it 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).
For more details on VRscans, please see the VRscans documentation space for information on downloadable sample scenes and Frequently Asked Questions or visit the VRscans.com website.
UI Paths
||mat Network|| > V-Ray > Material > VRscans
||out Network|| > V-Ray Render Elements node > V-Ray > Material > VRscans
Node
The BRDFScanned node provides inputs for controlling various material properties. They correspond to parameters in the section below.
Common Parameters
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.
Clear Coat Mult – Specifies a strength multiplier for the material's clear coat if applicable.
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.
Filter Color – A color multiplier for the material sample and can be used to tint the material (it affects the color of the reflections as well as a post effect).
Advanced Parameters
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.
Depth Mult –Specifies a strength multiplier for the depth.
Tint – Specifies a color for tinting the material.
Bump Mult – The coat layer has a built-in bump map stored in the material sample file. This controls the strength of that bump.
Bump Start – Specifies the starting threshold for the built-in bump map.
Clear Coat Bump – 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.
Clear Coat 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.
Clear Coat Highlights – Enables highlights from point light sources for the coat layer.
Map Channel – Specifies the channel for mapping.
Plain Materials – A strategy used for material display. It controls the visibility of textures (if present). Possible values are:
None – The full material evaluation is always used. The object must have valid UV coordinates.
Average 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 anisotropic.
Average symmetrized BRDF – Averages the BRDF and removes any anisotropy. This mode can be used on objects without proper UV coordinates.
Scramble – Useful to reduce tiling artifacts for isotropic materials with small details like car paint with flakes.
Scramble Size – Determines the size of the pieces that are continuous in the uv space, measured in centimeters. Only available when Plain Materials is set to Scramble.
Scene Scale – Specifies a percentage for the original scene units of the scene.
Direct Light Multiplier – Specifies a strength multiplier for the material's direct lighting.
Reflected Light Multiplier – Specifies a strength multiplier for the material reflection.
GI Lighting Multiplier – Specifies a strength multiplier for the material's global illumination.
Transparency Multiplier – Specifies a strength multiplier for the material transparency.
Sampling Type – Determines which samples are taken around pixels involved in "blurry" effects such as anti-aliasing, depth of field, indirect illumination, area lights, glossy reflections/refractions, translucency, motion blur, etc.
Importance sampling – Bases the number of samples allocated to a value on the importance when it comes to things like distance from the camera or if more samples are needed to render a realistic result.
Uniform sampling – The number of samples is the evenly taken over the entire image.
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 this option is controlled by the global Render 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.
Subdivs – Controls how many reflection rays will be traced for the material. Note that the material does not have a "diffuse" or "reflection" component; everything is considered glossy reflection. Note that this parameter is available for changing only when Use local subdivs is enabled in the DMC Sampler.
Retrace – Improves the precision of Global Illumination in cases where the light cache produces too large an error. This is especially obvious near corners where light leaks might be possible because of the light cache interpolation.
Don't use GI for Primary Rays – An approximation of Global Illumination for improving rendering speed. Controls whether to use GI for primary (camera) rays.
Displace – Enable displacement if supported by the material.
No Transparency – Turns off transparent properties of the material.
Dome – Enables or disables dome lighting.
Disable Enlargement – Disables the material from being enlarged.