The Maxwell Material shader operator stands for the layered material system used by Maxwell Render. Maxwell Render’s materials are made up of different “components” such as BSDF (Bidirectional Scattering Distribution Function) and Coating, Emitter or Displacement. These components are organized into layers which are stacked one on top of the other. This special hierarchy is represented by tabs and multilist controls on the interface of the Maxwell Material node.
Image Removed
Image Added
Material properties
| Section |
|---|
| Column |
|---|
|
| Column |
|---|
The main tab of the Maxwell Material node contains the following global properties. - Load MXM: load the material description from the specified .mxm file. The SHOP node is renamed to the name of the loaded material.
- Reload: updates the parameters from the .mxm file. This button is useful if the .mxm file has changed outside Houdini (for example edited with the Material Editor).
- Save MXM: exports the material to the given .mxm file.
- Show Preview: calls Mxed to calculate preview of the material by the current settings. The preview image is displayed in MPlay.
- Edit in Material Editor: opens the Material Editor (Mxed) with the current parameters which provides a user-friendly interface to edit the material. After the material is saved and the editor is closed, the plug-in reloads the material parameters automatically.
- Dispersion: enables / disables the dispersion calculations. Dispersion is the effect which can be seen when different wavelengths of light are refracted at slightly different angles as they pass through a material. The amount of dispersion can be controlled with the Abbe parameter of the BSDF component.
- Shadow: enables / disables the shadow catcher, used for compositing purposes.
- Matte: enables / disables matte properties for this material.
- Material ID Color: specifies color identifier for the material, useful for compositing.
- Global Bump Mapping: enables using global bump map which will affect the whole material, alongside the bump of each individual BSDF.
- Bump Strength: specifies the strength of the bumps.
- Bump Texture: specifies a bump texture where brighter values will create bumps on the surface and darker values will create indents. A color map can be used as a bump map but only the grayscale information of the map will be used.
- Use Bump Texture As Normal Map: if checked, the given bump texture will be used as a global normal map. A normal map has the advantage specifying an angle, or the direction of the bumps while bump map can simulate only the up / down direction.
|
|
...
| Section |
|---|
| Column |
|---|
 |
| Column |
|---|
The coating component has the following parameters: - Enabled: enables / disables visibility of the component.
- Name: name of the Coating component.
- Thickness: specifies the thickness of the coating component. Can be specified by a numerical value or through a weight map. To avoid interference coloring, higher thickness values (such as 1 mm = 1000000 nm) should be used.
- Min / Max: specifies the minimum and maximum value of the thickness used with a thickness map only. The thickness map will be treated as a grayscale map using the given range.
- Use IOR: allows users to set the value of the index of refraction (Nd) manually.
- IOR File: specifies an .ior file which provides Maxwell Render with the exact index or refraction for each wavelength of a material. These materials have the advantage of being extremely realistic, but complex IOR data requires more complex mathematical functions.
- Reflectance (0°): specifies the light reflected by the material, when the object is seen at 0° degrees (frontal view).
- Reflectance (90°): specifies the light reflected by the material when the object is seen at 90° degrees (glancing angle).
- Nd: specifies the overall reflectivity of the object (IOR: index of refraction). With transparent materials the Nd also controls the amount of refraction.
- Force Fresnel: specifies behaviour of the reflectance between 0° and 90° (the Fresnel curve).
- K (extinction coefficient): specifies the amount of absorption loss when an electromagnetic wave propagates through a material. This coefficient plays role in the calculation of the refraction at a particular wavelength.
- Use R2: gives controls over the falloff between the 0° and the 90° color.
|
|
Displacement properties
| Section |
|---|
| Column |
|---|
 Image Removed |
| Column |
|---|
Contrary to bump / normal maps which simulate grooves on the surface, the displacement component simulates real geometry at render time as if it was actually modeled. This feature is very useful for adding fine detail to a mesh which would otherwise be difficult or impossible to model. Maxwell supports both 1D vertical displacement (also known and Height Map) and 3D displacement (also known as Vector Displacement). |
|
| Section |
|---|
| Column |
|---|
 Image Removed |
| Column |
|---|
Projection properties- Channel: specifies the UV set (set of UV coordinates) to be used for the texture. An object can have several UV sets in Maxwell Render, for example a cubic and spherical UV set. The UV sets are numbered from 0.
- Method: specifies the tiling method of the texture. Possible values are:
- X axis
- Y axis
- Both X and Y axis
- No tiling
- Relative / Meters: specifies the tiling mode.
- Relative: the amount of tiling is set in texture coordinates.
- Meters: the amount of tiling is set in real scale (meters). Maxwell Render will use a 1m x 1m x 1m UV set for the texture when the Meters option is selected, regardless of the actual size of the object and what other UV sets may be applied to the object. This is useful to create re-usable materials independently of the size of the object.
- Repeat: specifies the tiling amount (number of repetitions) of the texture.
- Offset: specifies the amount of offset for the X, Y axis.
Image properties- Invert: inverts the loaded texture. This is useful for black & white textures used as a weightmap or mask.
- Alpha Only: uses only the alpha channel of the image when it exists.
- Interpolation: applies filtering to the texture which is useful to avoid pixelization of smaller textures. Filtering is handy mostly for displacement textures – to smooth out the displaced surface – especially when using 8bit textures. But interpolation can cause blurring to regular (color, bump, weightmap, etc.) textures.
- Brightness: specifies the brightness of the texture.
- Contrast: specifies the contrast of the texture.
- Saturation: specifies the saturation of the texture.
- RGB Clamp: specifies the maximum darkest or brightest values in the texture.
Normal map propertiesWhen editing normal map properties, the options Flip X, Flip Y, and Wide specify how the normal map was created. The most common standard is ‘Flip Y’, so this is selected by default. This option depends on the application used to create the normal map- Enabled: enables the displacement component.
- Texture: 8, 16 or 32-bit grayscale texture to define the geometric detail.
- Type: defines the type of the displacement method.
- On The Fly: unique displacement technology that allows you to create virtually unlimited detail while using very little extra memory. Recommended for very fine, smaller/medium displacements and when the RAM consumption needs to be prioritized.
- Pretessellated: 1D height map displacement. Recommended for general purposes when the RAM in the system is not a limitation, and it renders much faster than the On The Fly method.
Vector: an RGB color map displacement holding information for both the X, Y and Z coordinates of each point. As points can be displaced in the three axis, this type provides a surface with richer detail than simply 2D displacement that uses black & white height maps.- Subdivision defines surface accuracy, ability and response to detail, independent of texture resolution. It is a measure of the subdivision level of the mesh. Higher value means more accurate result, but also longer render time because of the more render time subdivision of the mesh.
- Adaptive: when this option is checked always the most detailed displacement will be created that a given texture can provide.
- Offset: specifies which gray level in the texture represents zero displacement.
- Smoothing: controls whether the displaced surface should render smoothly (continuous shading) or render faceted. This flag is independent of the object’s smoothing angle setting.
- UV Interpolation:defines the interpolation method of the UV coordinates for the new geometry.
- None: no boundary interpolation behavior occurs.
- Edges: all the boundary edge-chains are sharp creases; boundary vertices are not affected.
- Edges and Corners: all the boundary edge-chains are sharp creases and boundary vertices with exactly two incident edges are sharp corners.
- Sharp: smooths only near vertices that are not at a discontinuous boundary. All vertices on a discontinuous boundary are subdivided with a sharp rule (interpolated through).
- Height: specifies the maximum distance displaced on the base mesh. This value needs to be greater or less than zero for displacement to appear. The white of the displacement map will be raised to the given height. The displacement height can be set in percentage or absolute units.
- Percentage (%): relative to the longest edge of the associated object’s bounding box. Using relative height is useful to preserve the same displacement height when scaling the object.
- Centimeters (cm): absolute height to displace regardless of the object dimensions.
- Preset: TODO
- Transform: TODO
- RGB Mapping: TODO
- Scale: controls the overall size of the displacement for vector displacement methods.
|
|
Texture properties
Each texture of the material components has special properties which can be set in a dialog window after pressing the 
Image Removed button next to the texture field.
Material palette
The easiest way to create a material is browsing the default Maxwell materials using the Material Palette window which can be found in the Windows menu. It has a group called Maxwell where the following materials can be added to the scene:
...