Blender 2.5 SLG exporter materials
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Object Material properties
The SLG Blender exporter (SLGBP) is material-centric. It's a good idea to name your Blender materials as mesh data is stored grouped by material. The material name is used for the PLY filename.
The types of materials in SLG are:
- Architectural Glass
- Real Glass
- Exit Portal
The SLG Blender plugin makes use of existing Blender fields in order to select and adjust the materials and their values. Play close attention to the below to see exactly how to modify materials, as it can be a little tricky and many of the Blender fields are not used by SLG.
You can optionally also manually edit the outputted SCN file to further make adjustments to your materials in ways that the exporter cannot.
scene.materials.matte.YourMaterialName = 0.8 0.8 0.8
Matte is a plain colored material without shine. It is very quick to render, but is not very realistic in most cases. Matte is also the default material an object gets assigned in SLG if one is not specified.
The only setting available is the 'Diffuse Color' in Blender. This is not only the color of the object, but also controls how much light is reflected.
It is recommended to keep the total color value between 0 and 0.8 (the highest of your R, G, or B values). You may find it easier to look at the HSV color picker and then just make sure 0 > V <= 0.8.
Values greater than .8 will work, but tend to look less realistic and contribute more noise. In fact, values greater than 1.0 will actually reflect more light than they receive (acting as a kind of "light amplifier"), which is also unrealistic and a potential source of noise.
Also be careful not to use 0 for black, as that will absorb ALL light and no detail will be visible on your object (use a very small value instead, like V=0.025).
Here are some examples of Matte objects:
scene.materials.metal.YourMaterialName = 1. 1. 1. 100. 1
The Metal material produces a shiny, metallic appearance on your objects, and can be used to create a variety of metals, such as gold, copper and silver. Settings include the base metal color of metal, the sharpness of the reflections, and whether or not to produce reflective caustics.
Metals are enabled by checking the Mirror checkbox in Blender, setting the Reflectivity slider all the way up to 1, and setting the Gloss value to something <1.
Note that setting the Gloss value exactly equal to one will actually change the material type to Mirror in SLG (see Mirror section for details).
Also, setting the Reflectivity to less than 1 will actually change the material type to MatteMetal in SLG (see MatteMetal for details).
The Reflection Color sets the base color for metal.
The Gloss amount controls how sharp the reflections are (keep <1 or the material will be changed to Mirror).
The Depth value will enable/disable caustics (0 = disabled, >0 = enabled).
Here are some examples of metal will various colors and gloss:
scene.materials.mattemetal.YourMaterialName = 0.6 0.6 0.6 0.4 0.4 0.4 100. 1
Like the name suggests, mattemetal is a cross between the matte and metal materials and produces a glossy object. It can be useful for creating the look of a painted metal or colored object with glossy coating.
You can set the base diffuse color, amount of reflectivity, color of the reflection, sharpness of the reflections and whether or not it should produce reflective caustics.
Diffuse Color sets the basic matte color of the object.
Reflection Color sets the reflection color (or tint of the coating).
Reflectivity sets what percentage of light should be reflected back to the viewer (i.e. how shiny the material is). NOTE: Keep it >0 or the material will change to Matte, and <1 or the material will change to Metal.
NOTE: The value of the Diffuse Color plus the Reflectivity value (not reflection color) should be <= 1, or the material will be emitting more light that it is receiving (not realistic and could lead to longer render times).
Gloss controls how sharp the reflections will be. NOTE: Keep it under 1.0 or the material will change to mattemirror (see the mattemirror section for details).
Depth controls whether or not the material produces reflective caustics. 0 = no caustic, >0 = caustics enabled.
Here are some example of mattemetal object with various settings:
scene.materials.alloy.mat_alloy = .5 .5 .5 .5 .5 .5 99 0.8 1
Alloy is a metal-like material similar to MatteMetal, but the amount of reflection changes with the viewing angle.
scene.materials.archglass.YourMaterialName = 0.5 0.5 0.5 1. 1. 1. 1 1
Architectural Glass is a special use case material, meant only for windows that are between the light source and the rest of your scene. Due to the nature of the path tracing algorithm, the Real Glass material tends to block a lot of the light and cast shadows, and is therefore poorly suited for windows. For any other objects made out of glass (wineglasses, etc.), use the Real Glass material instead.
IOR (index of refraction) must be set to 1.000 to enable Architectural Glass.
Diffuse Color is the base tint of the glass.
Reflection Color is the tint of the reflections in the glass.
Depth will enable/disable reflective caustics. (0 = disabled, >0 = enabled).
(Sample images needed)
scene.materials.glass.YourMaterialName = 1. 1. 1. 1. 1. 1. 1.0 2.419 1 1
Glass transmits some light (the Diffuse color) and reflects some light (the Reflection color) controlled completely by the IOR (index of refraction) value. This material is great for glasses, gemstones, or other glass and glass-like objects. For windows that have a light source behind them, however, it is best to use Architectural Glass instead (see Architectural Glass section for more details).
Diffuse Color sets the base tint color of the glass. (For clear glass, make the RGB values 1, 1, 1 or you will get a darkening effect).
Reflection Color sets the color of the reflections. (Make the RGB values 1, 1, 1 in most cases).
IOR sets the inside IOR (index of refraction) of the material, controls how the lights is reflected and refracted. Here is a list of real-world IOR values of various objects (glass, diamonds, etc.)
Depth (in the Transparency panel) controls whether or not reflective caustics are enabled. 0 = off, >0 = on.
Depth (in the Mirror panel) controls whether or not transmission caustics are enabled. This makes glass look much brighter and better, but does take longer to render. 0 = off, >0 = on.
Note that the Outside IOR can be manually changed by altering the 7th value in the glass material's line of the SCN file. The default is 1.0 (air), and it is only necessary to ever change this if your object is in some other medium (for example, bubbles in water).
Here are some examples of real glass with various IOR values and both kinds of caustics enabled:
scene.materials.light.YourMaterialName 0.8 0.8 0.8
The light material is used for creating a mesh emitter light source in your scene. The Diffuse Color controls what color the light will be, and the Emit slider controls the brightness/power.
To make an object a Light, simply set the Emit value to something other than 0. Light will emit from the object in the direction that the normals face.
NOTE: For faster render times and fewer fireflies, use only very simple objects as lights. It is very common to use a regular plane as the emitter (make sure the normal is facing toward your scene).
Though not technially an SLG material, it is assigned to an object in the material panel. An object will become an invisible Exit Portal if the Shadeless box is checked.
An Exit Portal is a helper to speed up render times if HDR image-based lighting is used in a scene (see Lighting section), typically in an enclosed area such as light coming through a window. Placing an Exit Portal at the window will tell SLG to focus on light rays going through the portal and disregard other ones that won't affect the viewable part of the scene anyway, which can noticeably improve your render times.
Again, this is only applicable if your scene is using HDR image-based lighting and your scene is in a semi-enclosed area - otherwise an Exit Portal will have no effect.