Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

Overview

...

Section
Column
width50%

The VRayScannedMtl material allows the rendering of scanned BRDF material data stored in .vrscans files. These files are produced by Chaos Group's own internal material scanner and accompanying material creator software.

 

Note

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, but otherwise it should be able to render the sample scenes below.

 

The scanned material renders the captured the 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, that has been scanned with special scanner hardware. The material goes going beyond single-point BRDF capture and can to faithfully represent the textured appearance of a large number of real-world surfaces surface using bidirectional texture function (BTF) approximation. Because the scanned material simply reproduces 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.

Note

The VRayScannedMtl material is designed to be used with a licensed version of the VRscans software. The material will still render without a license, but the material's UI will not display and any renderings will include a watermark.

The scanned material simply stores information about the way a physical material responds to light , is at individual points on the surface; it has no notion of "diffuse" or "reflection" components, "normal" or "bump" maps.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.

Currently the material can render only opaque and transparent surfaces. Also, for the moment except for aside from 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.

Column
width5%

 

Column
width45%

...

UI Path: ||Material Editor window|| > Material/Map Browser > Materials > V-Ray > VRayScannedMtl

 

Parameters

...

General

 

Image RemovedImage Added


 

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 and by . By clicking on a point over a given object, the texture tiling is modified so that the texture is with the correct size for the clicked point.

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.

Plain materials strategy – Simplifies the shading of the material and may help to reducing tiling artifacts. 

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 symmetrize 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.

Filter color2-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.

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.

Effect ID – Specifies the Effect ID number.

Information – Displays some useful information contained in the .vrscan file, such as the actual material sample size.

 

Appearance

 

Image Added



 

Filter Color – A color multiplier for the material sample and can be used to tint the material.

Information – The text field displays some useful information contained in the .vrscan file, like the actual material sample size.

 

Advanced

 

Image Removed

Subdivision (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.

Advanced


Image Added


 

Subdivisions – Controls how many reflection rays will be traced for the material. Note : The that the material does not have a " diffuse " or " reflection " component - , and that everything is considered glossy reflection.

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 of the renderer settingsSwitches 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 cut-off Cutoff threshold of the VRayMtl material material.

Glossy as GI – Useful for debugging purposes and is equivalent to the same setting in the VRayMtl material.

Coarse indirect – Simplifies the calculations of the material when it is viewed through GI rays. In that case the Average BRDF method is used to shade the material (see above).Don't use GI for rays shorter than – Defines the ray distance threshold below which GI caches will not be used to contribute for indirect illumination, but instead new secondary rays will be spawned. For example, if a ray hits any geometry that is too close to the ray's starting point, this will force the use of Brute Force GI for tracing additional secondary rays instead of using the GI cache.

Plain materials strategy – A strategy used for material display. It controls the visibility of textures (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 representaion of the material with no maps visible.
Scramble – Uses blocks from the photo samples in the material. Useful to reduce tiling artifacts for isotropic materials with small details like car paint with flakes.

Color space – Specifies between sRGB, Adobe RGB and Pro Photo color space models.

Don't use GI for primary rays – GI caches will only contribute to indirect rays. By default this option is enabled (i.e. GI is not used for primary rays) to ensure better realism of materials. It makes sense to disable this option when the scene lighting is relatively even from all directions, as it will speed up the rendering but will likely cause no loss of image quality.

Uniform reflection 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. Which method will 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.

 

Clearcoat

 



Enable – Enables the tracing of a clear coat layer for the material.

...

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 into in the material sample file. This allows you to control the strength of that bump.

...

This is a standard 3ds Max rollout used to control how the material is applied to objects.

 

Material Optimization

...

When using this material, there are certain settings that can optimize quality and rendering time.

Antialiasing Settings

The easiest way to optimize antialiasing is to use the Progressive Image Sampler. This approach can be a little bit slower but it doesn’t require complete understanding of the sampling in V-Ray and will work for any scene. The settings to use in the 3ds Max Render Setup window are:

Sampler type: Progressive
Min Shading Rate:
1
AA filter:
Enabled
AA filter type:
Lanczos
Size:
2.5
Min subdivs:
1
Max subdivs:
200
Noise threshold:
0.01
Max. render time (min):
 you will set Set this value based on to the maximum render time you want V-Ray to render forwould like to use.

 

 

 

Using the Adaptive image sampler can sometimes produce the same result for in slightly faster render times, but it requires that you experiment with different settings and have a good understanding of how sampling works inside V-Ray.

...

The V-Ray Scanned material is a purely reflective material (it doesn’t have a diffuse component), this . This means that for scenes that are comprised of V-Ray Scanned materials entirely you do not need to enable GI.

If you still want to use GI global illumination, use the settings below in the Global Illumination rollout:

Primary Bounce (Primary engine): Brute Force – use the default settings for Brute Force
Secondary Bounce: (Secondary engine)
Light Cache
Subdivs
: 2000 for simpler exterior scenes and 4000 for interior scenes where light bounces a lot
Sample Size
: 0.02
Store Direct Light:
Enabled
Use light cache for glossy rays (Use for glossy rays):
Enabled
Filter type (Filter):
None
Prefilter:
Enabled
Prefilter samples:
10
Depth (Bounces):
10
Use retrace threshold (Use for glossy rays):
Disabled

...

Subdivisions: 8
Trace Depth
: 5
Cut off:
0.01
Retrace (Don’t use GI for rays shorter than):
0
Displacement (Edges Displacement):
only enabled  Only enable when there are close-ups of materials that have some with bumps.
No Prim GI (Don’t use GI for primary rays):
Enabled

...