Material edition is one of the authoring tool available in designer mode. It enables you to adjust values, replace or add new textures to achieve realistic effects on your model.
Panel
To show the material edition panel, click on the material of your choice in the model tree on the left.
Material in the model tree (left) or the quick access (right)
Initially, the current settings of the material are displayed.
A selected model and the material panel opened on the right
The panel is composed of different sections that regroup the parameters of the material. For most of the sections the same inputs are available:
The slider changes the value of a numeric parameter in a range. Select and move the handle to adapt the value, or directly enter a precise number in the text field. Arrows can be used to set the parameter to the minimum or maximum value.
Slider set at maximum value (left) and moving (right)
The color picker displays the current color of the parameter and can open a tool to select a specific color and transparency. It is associated with 3 or 4 sliders to precisely define each component if necessary. To display the color palette, click on the color area. Reset the color to its default value thanks to the small round white button in the bottom right corner of the color area.
Color palette of the color picker
The texture slot displays the texture currently applied to the parameter, and can open a window to add, replace or remove it. To edit the texture, click on the texture slot then:
remove the current texture by clicking the cross at the right of the name,
replace or add a texture by clicking the text field which displays the name of the texture or the 'upload texture' instruction.
Save or cancel your choice to close the window.
Texture window with no texture set
Wrapping options control how a texture is repeated in horizontal and vertical directions along the surface based on its texture coordinates. Three values are available for each direction: No Repeat, Repeat and Mirrored Repeat. Default is Repeat. See the full explanation later in the article.
Wrapping options and the 3 possible values
Parameters
The material panel enables the edition of PBR (Physically based rendering) material. To learn more on the different parameters and their meaning, consult this article.
Base color
The base color section is composed of a color picker (+ 4 sliders) and a texture slot. The color and the texture are combined to define the base color of the material.
If no map is applied to the texture slot, playing with the sliders or the color picker directly changes the resulting base color of the material.
Material with a white base color (left) and a green base color (right)
A map can be applied by opening the texture window and selecting an appropriate texture through the file explorer.
Image picked as base color map on the file explorer
The texture displays in the texture slot and is visible on the material. The color can be still edited to tint the texture as the effects of the color and the texture are combined (values are multiplied). To keep the texture as the only source of base color, set the color to white (which is the default value of the color).
Material with a white base color (left) and a pink base color (right)
Metallic workflow
This section defines the metalness and the roughness of the material. Those parameters are defined by a texture and values that combine.
Editing the metalness and roughness value gives the material an aspect metallic or plastic.
Different values of roughness
Selecting a texture allows to vary the values along the surface textured by the materials. A single texture groups both the metalness and roughness values: the green channel (g) encodes the roughness and the blue channel (b) the metalness. The red channel (r) can then be used to code another value such as the occlusion (later described).
Green and blue channels of the textures are used to code roughness and metalness
Once applied, the texture effect can be modulated by the values exposed by the slider. The numeric values multiply the texture.
The values combine with the texture to create the final effect
Normals
The normals section exposes the texture that can modify the normals of the material to fake details that cannot be directly designed by the geometry.
The normal map adds grain to the object
Occlusion
The occlusion section is a texture used to simulate soft shadows caused by the geometry of the model itself, that occludes a bit the ambient lighting in some areas. Only the red channel (r) of the texture participates to the occlusion value.
Red channel of the texture is the source of occlusion
Emissivity
The emissivity section counts a color picker and a texture slot. The color and the texture are combined to define the emissive contribution of the material. It defines the light emitted by the material, allowing to simulate screens, lights items... As the color multiplies the effect of the texture, it is possible to use a black and white texture colored afterwards. If only the texture is needed, the emissive color must be set to pure white as the default value is pure black (meaning that the final value is pure black too). On the texture only the emitting areas must be valued. On the opposite, a uniform emissivity can be achieved by setting a color only.
Emissive texture defines a digital screen displaying time and temperature
The emissive color modulates the values of the texture
Opacity
The opacity section controls how transparent the model is, and how transparent areas should display. It works in combination of the alpha contribution of the model's base color which is the direct transparency value for the material. It means that transparency can be defined globally trough the alpha channel of the color, or locally in specific areas of the base color texture (note: the texture must define an alpha channel like the PNG format).
Texture including a transparent stripe just above the logos
The main control is an option selector that exposes the available modes:
Transparency behavior is controlled by 3 options
opaque: the model is never transparent whatever the alpha value coming from the color or the texture
In opaque mode, transparency is ignored
blend: the model is transparent according to its alpha contribution. The transparency of the color and texture combine. Other objects can be seen through transparent parts
Transparency is controlled globally with the alpha component of the color (left), locally with map (middle) or is the result of the combination of the 2 (right).
mask: the model is totally transparent in areas where the alpha values are under a specific value that acts as a 'all or nothing' filter. It comes with an additional slider named 'Alpha Cut Off' used to precise this value.
If an area of the base color texture defines a transparency of 0.396, it will be totally opaque when the alpha cut off is 0.39 and fully transparent when it is set to 0.40. As a reminder, the transparency value is the combination of the texture transparency and the color transparency (alpha component). If the alpha component is set to 0.5, the resulting transparency of the area will be 0.396 * 0.5 = 0.198 that would be the new minimum value of the alpha cut off to take it into account.
Transparent area of the map is ignored (left) or made fully transparent (right)
Double Sided
This section exposes an option to render both sides of 3D surfaces covered by the material. It is used when the model interior space is exposed though holes or transparent areas, while avoiding to duplicate the geometry to make this space visible.
Note: that option may affect the rendering performance of the model, as it acts as if 2 different versions of the parts covered by double sided materials should be rendered.
The interior space is invisible (left) or visible (right) according to the chosen option
Wrapping
Each texture has wrapping options that describe the repetition of the texture along a surface. The texture mapping is control by the texture coordinates. The reference coordinates vary between 0 and 1. Then when coordinates are over 1 or below 0, texture is repeated in the way defined by the wrapping options.
Texture repeated on a surface with a large range of texture coordinates
Three values are possible for a specific direction:
No Repeat: the texture is not repeated out of the range [0, 1]. The borders of the texture are just extended in both ways.
Repeat: the texture is repeated in each range of coordinates [n, n+1]
Mirrored Repeat: the texture is repeated but reversed in each range of coordinates [n, n+1].
The combinaison of values give 9 possibilities:
Texture applied on a geometry with different wrapping options
Related: