This page provides some details in the settings available when using the Scanned Material in V-Ray.
The VRayScannedMtl 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 VRayScannedMtl 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).
||Hypershade|| > Create panel > VRay section > VRay Scanned Mtl
||Create Render Node window|| > VRay section > VRay Scanned Mtl
||V-Ray Shelf|| > Right-click to Create V-Ray Materials button > VRay Scanned
Scanned material file – The file name with the data for the scanned material; usually has a .vrscan extension.
Viewport Color – A color/texture used for previewing the material in a Textured viewport.
Show UV Borders – Displays the borders of the material tile in the viewport on the object(s) that have the material applied to it. This only works with the DirectX viewports.
Tiling Factor – Global multiplier for U and V coordinates.
Two Sided – Enables both sides of the material.
Disable Transparency – Turns off transparent properties of the material.
Adjust UV tiling (button) – The .vrscan file stores information about the physical size of the scanned sample and by clicking on a point over a given object, the texture tiling is modified so that the texture is the correct size for the clicked point.
Information (area) – The text field displays some useful information contained in the .vrscan file, like the actual material sample size.
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 subvis is enabled in the DMC Sampler Settings.
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.
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.
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.
Color Space – Choose between sRGB, Adobe RGB, and Pro Photo color space models.
Displace – Enable displacement if supported by the material.
No Prim GI – An approximation of Global Illumination for improving rendering speed. Controls whether to use GI for primary (camera) rays.
Retrace – Improves the precision of Global Illumination in cases where the light cache will produce too large an error. This is especially obvious near corners where light leaks might be possible because of the light cache interpolation.
Use Filter – Enables the use of the color filter.
Filter Strength – Multiplies the effect of the 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).
Use Paint – Enables the use of Paint Color.
Paint Strength – Multiplies the effect of the paint.
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.
Gamma Correction – 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 VRayCarPaintMtl. 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.
Clear Coat Refl – Enables the tracing of a clear coat layer for the material's reflection.
Clear Coat Hilights – Enables highlights from point light sources for the coat layer.
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 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.