Phong reflection model is an historical technique that describes the way a surface reflects light. It generates diffuse reflections from rough surfaces and glossy reflections from shiny surfaces - based on the fact that shiny surfaces have small intense glossy highlights, while dull surfaces have large highlights that fall off more gradually.

Phong Material

• Diffuse Color - This attribute defines the base color and the main characteristic of the material. Use the slider to change the brightness. Click the color field on the right to open the color chooser. Assigning a texture to the diffuse color projects it onto the surface. The appearance is a combination of the defined color and the assigned texture.

• Glossy Color - Sets the material’s color for surfaces glossy reflections. Use the slider to change the brightness. Click the color field on the right to open the color chooser. Assigning a texture to the glossy channel defines areas in which different gloss intensities appear with the help of a texture. The glossy color depends finally on both - the defined color and the possibly assigned texture file.

• Roughness - The roughness parameter controls light reflections on top of the surface. The higher the value the rougher the microscopic structure on top of the surface and the more diffuse are the reflections.

• Diffuse Backscattering - Defines the roughness of the material’s diffuse component. A value of 0.0 means smooth (Lambertian surface), a value of 1.0 means rough (for example, concrete).

Diffuse Texture

When the use of a previously saved texture is checked, the following parameters can be configured:

• Use Texture - Loads an image texture for the diffuse color channel. Uses the image as pattern on the surfaces.

• Use Image Sequence - Select when an image sequence is loaded in the Use Texture box. An animation for the sequence is created in the Curve Editor. Go to Animation > Timeline. Click play to view the animated image sequence on the material.

  NOTE For a group of images to be considered an image sequence, there must be at least two images with the same name with an increasing numeric value. The required naming format is name, number, and extension. For example, image000.png image001.png.

• Frame Offset - Sets an offset to the image number when an image sequence is loaded in the Use Texture box and when Use Image Sequence is selected.

• Inline Image Sequence - When selected, loaded image sequences are packaged within the .vpb file. If the .vpb is moved to another computer, the image sequence does not need to be moved separately.

• Use Alpha - If the image texture has an alpha channel embedded, it is used.

• Link texture Settings - If this option is selected for multiple texture slots of a material, their texture mapping settings are linked together. When changing, for example, the Repeat UV of a linked texture, it is changed for all linked textures at once. When selecting this option for a texture while other textures of that material already have the link option selected, the texture settings are set to the settings of the already linked textures.

• Mapping Type - Type of mapping can be selected. It can either be Planar, UV, or Triplanar.

• Use Texture Size - Select to defined texture size in millimeters instead of repeat values for texture mapping. Only available when Mapping Type is set to UV. Use Texture Size only works on objects with UVs set to real world scale. If the UVs have not been scaled, go to the UV Editor and use Apply World Scale.

• Texture Size - Enter the width and height of the texture in millimeters. Only available with mapping type UV and Use Texture Size selected or with mapping type triplanar.

• Repeat Mode UV - Sets the repeat mode of the texture. There are four modes, which can be set:

  • Repeat - Repeats the texture in all directions.
  • Mirror - Repeats and mirrors the texture on the x-and y-axis with every repetition.
  • Decal - The texture is not repeated.
  • Clamp - Repeats only the last pixel of the texture is repeated.

  For Mapping Type UV you can set the following parameters:

  • Repeat UV - Sets the number of repetitions for the UVs.
  • Offset UV - Sets the offset for the UVs.
  • Rotate - Rotates the UVs.

  For Mapping Type Planar you can set the following parameters:

  • Projection Center - Coordinates (x, y, z) of the projection center can be set here.
  • Projection Orientation - Offers the possibility to incline the projection plane.
  • Projection Size - Sets the size of the projection.
  • Keep Aspect Ratio (Checkbox) - If selected, the size, corresponding to the original aspect ratio of the texture, is automatically adjusted.
  • Rotate - Sets the projection plane’s rotation on the X/Y/Z-axis.
  • Manipulate - Applies the texture to the selected surface.
  • Fit Size - Adjusts the size of the projection plane to the selected object.
  • Object Center - Adjusts the projection center to the center of the selected object.

  For Mapping Type Triplanar you can set the following parameters:

  • Edge Blend - Sets the range for overlapping areas of the planar projection.
  • X Repeat UV, Y/UV, Z/UV - Set the repetition value of the U and V-axis for each projection direction.
  • X Offset UV, Y/UV, Z/UV - Set the offset value of the U and V-axis for each projection direction.
  • X/Y/Z Rotate - Sets the projection orientation.

• Anisotropy - Sets the texture filter quality for the image texture. One is lowest quality, 16 is highest quality.

• Input Gamma - Sets the texture image gamma correction.

• Use ICC Profile - If selected, the texture’s colors are interpreted based on an embedded color profile if present. If a color profile is missing, it is assumed that the colors are stored in sRGB.

Glossy Texture

When the use of a previously saved texture is checked, the following parameters can be configured:

• Use Texture - Loads an image texture for the glossy color channel. Uses the image as a pattern on the surfaces.

For further information on the common settings, refer to the Phong Diffuse Texture section.

Roughness Texture

Use a roughness texture for varying roughness values on the surfaces. If a previously saved roughness texture is selected, the simple roughness slider loses its function. Instead, you can define how the texture values are mapped to roughness values using a minimum and a maximum roughness value. The following parameters can be configured:

• Use Texture - Load an image texture for the roughness channel. Using a grayscale image is recommended, for color images the red channel is used.

• Minimum Roughness - Defines the roughness value to which a texture value of 0 is mapped.

• Maximum Roughness - Defines the roughness value to which a texture value of one is mapped.

For further information on the common settings, refer to the Phong Diffuse Texture section.

Bump Texture

Bump mapping enables the creation of structure to the materials surface.

• Use Structure - Uses a default noise map.

• Use Texture - Loads an image texture for the bump channel. Uses the loaded image as a pattern on the surfaces.

• Parallax Intensity - Sets the parallax shift interpretation of the bump image texture.

• Bump Intensity - Sets the bump intensity interpretation of the bump image texture.

• Structure Size - Sets the structure size when the procedural bump structure is activated.

• Bump Type - Sets the bump type. The bump mapping can be drawn as bump map or as pixel displacement map without self-shadowing.

For further information on the common settings, refer to the Phong Diffuse Texture section.

For further information on the Incandescence, Transparency, Subsurface Scattering, Displacement, Raytracing, and Common settings, refer to the General Truelight Material Settings section.