This page provides information on VRscans.
The VRayScannedMtl material applies material information gathered by the Chaos Group VRscans system to an object. The VRscans system captures the appearance of an actual physical material sample, going beyond single-point BRDF capture to faithfully represent the textured appearance of a real-world surface using bidirectional texture function (BTF) approximation. The information is saved in a .vrscan file, which the VRayScannedMtl material then reads to reproduce the material in the rendering.
The VRscans system and VRayScannedMtl material are intended as a solution for users who need to exactly match a given real-world sample.
VRayScannedMtl requires a separate VRscans license. The material will still render without a license, but it will include a watermark and the material's UI will not display.
The scanned material simply stores information about the way a physical material responds to light at individual points on the surface; it has no notion of components that extend across the surface such as diffuse or reflection qualities, or normal or bump maps. The scanned material is simply a faithful representation of how each point on the object responds to light. The .vrscan files tend to be quite large.
||Material Editor window|| > Material/Map Browser > Materials > V-Ray > VRayScannedMtl
File – The file name with the data for the scanned material; usually has a .vrscan extension.
Reload – Refreshes the .vrscan file loaded in the material.
Viewport UV borders – Displays the borders of the material tile in the viewport on the objects that have the material applied. This only works with the DirectX viewports.
Adjust UV tiling to an object – The .vrscan file stores information about the physical size of the scanned sample. 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.
2-Sided – Forces the back-facing polygons to be shaded in the same way as the front-facing ones. If this option is disabled, the back-facing polygons will appear black. This can be useful for objects like curtains. Note that this option is always considered enabled when rendering transparent materials.
Detect Mapping Issues – Checks if the UV mapping has the necessary quality. Some scanned materials require very precise UV mapping. With this tool you can check the UV mapping before starting a lengthy render.
Disable transparency – Disables transparency for materials that store such information. This can be useful for speeding up the rendering, especially when the transparency produces little or no effect.
Use triplanar mapping – Ignores the object's default UV mapping and assigns one with U and V axes parallel to the nearest object-space axes.
Random offset – Randomizes the material offset.
Random rotation – Randomizes the material rotation from one object to another.
Effect ID – When the value is greated than -1 it overrides the Material ID. The material mask values specified this way exceed in number the natively available in 3ds Max.
Information – Displays some useful information contained in the .vrscan file, such as the actual material sample size.
Filter Color – A color multiplier for the material sample that can be used to tint the material. (It will affect the color of the reflections as well. Acts as a post effect.)
Paint Color – Used to change the color of the material without losing the texture or changing the reflection color. For example, it can be used to changing the color of wood or leather without losing the material texture.
Gamma Correction – Adjusts the gamma of the material (including Filter Color and Paint Color if used) as a post effect.
Saturation – Controls the saturation of the material (including Filter Color and Paint Color if used) as a post effect.
Trace Depth – Controls the number of reflection bounces. A value of -1 means that the reflections bounces are controlled by the global V-Ray trace depth in the Global Switches rollout under the V-Ray tab in the Render Setup window.
Cut off – A threshold that is 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.
Bump and Parallax Zone – Determines the point where additional bump and parallax no longer exist and only natural height effects remain. This option is especially useful for shallow angles of view to the material, where it might appear flat or less detailed. A value of 0 adds no additional bump and parallax. Value of 1 adds additional bump and parallax equally regardless of the view angle. All scanned materials by default have the most suitable value loaded for this parameter to achieve the most realistic look. If you need full control over the bump and the parallax, set the value to 1 and work with the Parallax and Bump Multipliers.
Parallax Multiplier – Adjusts additional parallax and edge displacement strength.
Bump Multiplier – Adjusts the additional bump.
Plain materials strategy – Provides several interpretation modes for the textures inside the material (if present).
None – Used to view the material as it is with all the maps.
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 isotropic BRDF – Smooth representation of the material with no maps visible.
Color Space – Specifies between sRGB, Adobe RGB, and Pro Photo color space models.
Don't Use Cached Light (Pure Ray Tracing) – Allows you to disable the cached light for the material, ensuring physical accuracy without the need to switch off GI of the entire scene. Disabling this option results in faster, but less physically accurate render.
Uniform Spawning Distribution – When enabled, the material reflections are computed by sampling the hemisphere uniformly. When disabled, importance sampling is used to put more rays in directions where the material contribution is larger. One option does not always perform better than the other; performance depends on the scene lighting and the particular material that is used.
Edges Displacement – Uses a special technique that makes the edges of the geometry appear slightly jagged inwards. This option is useful when rendering close-ups of materials with bumps. It is faster than actual displacement and helps to achieve better realism.
Fast volumetric translucency – This option is relevant only to V-Ray scanned materials that are volumetric translucent. When this option is enabled, the calculation of the volumetric translucency is fast, but less accurate.
Enable – Enables the tracing of a clear coat layer for the material.
Highlights – Enables highlights from point light sources for the coat layer.
Strength – Specifies the strength of the coat reflections.
IOR – Determines the IOR of the coat layer, and from that 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 files typically contain the correct value for this parameter and it is set automatically when the file is loaded.
Bump multiplier – The coat layer has a built-in bump map stored in the material sample file. This allows you to control the strength of that bump.
Coloring – Turns the coat reflections colored.
This is a standard 3ds Max rollout used to control how the material is applied to objects.
V-Ray GPU render engine supports VRayScannedMtl under few limitations. In general, if your renderer is set to V-Ray GPU the unsupported features will be grayed out.
- Paint and Filter don't support texture maps;
- Fast Volumetric Transparency is not supported;
- Cut Off parameter is not supported.
VRayScannedMtl can make use of some of the Render Elements. Here is a list of those elements:
- Clear coat reflections stored in VRayReflection Render Element;
- Direct Light Contribution stored in VRayLighting Render Element;
- Indirect lighting by spawned rays stored in VRayGlobalIllumination Render Element;
- Material Opacity stored in VRayAlpha Render Element;
- Received caustics stored in VRayCaustics Render Element.