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OctaneRender® supports participating media inside objects. These settings are stored in Medium nodes, which are attached to the corresponding input pin of DiffuseAmount of diffusion, or the reflection of light photons at different angles from an uneven or granular surface. Used for dull, non-reflecting materials or mesh emitters. or SpecularAmount of specular reflection, or the mirror-like reflection of light photons at the same angle. Used for transparent materials such as glass and water. material nodes.
There are three types of Medium nodes: Absorption, Scattering, and Volume.
To render with Medium nodes, the Path Tracing or PMC render kernels are the best choice. It is possible to render MediumsThe behavior of light inside a surface volume described by scatter, absorption, and transmission characteristics. using the Direct Light kernel, but only if the Medium node is connected to a Diffuse materialUsed for dull, non-reflecting materials or mesh emitters., and if Diffuse Mode is set to GI.
Figure 1: Medium nodes are connected using the Medium button in the MaterialThe representation of the surface or volume properties of an object.'s parameters
Add Medium nodes to MaterialsA set of attributes or parameters that describe surface characteristics. applied to Meshes that define a closed volume. A single-sided plane will not work. For example, a plane representing a leaf will not work if you apply a Material with a Medium to it. The one exception is a plane representing the ground. OctaneRender® treats the ground plane as an endless, deep surface.
Specular materials are the best choice when using a Medium node. Set the TransmissionA surface characteristic that determines if light may pass through a surface volume. and Reflection parameters to a non-zero value, or a color other than black, or a Texture map.
Figure 2 : A Scattering medium node is connected to a Specular materialUsed for transparent materials such as glass and water.
When connecting a Medium node to a Diffuse material, set the Transmission to a non-zero value, or a Color other than black, or a Texture map.
Figure 3 : A Scattering medium node is connected to an Octane Diffuse material, a Float texture is connected to the Transmission input
When using a Specular shader, set the Reflection parameter to a low value because the part of the spectrum that is not reflected can enter the object for scattering. If the reflection is set to 1.0, all light gets reflected regardless of the Transmission value. If reflection is set to 0.0, all light gets transmitted through the surface. However, the result is an unnatural appearance. Reflection values of 0.1 - 0.2 are good starting points.
If the Reflection parameter uses a color, the light transmitted through the surface is shaded as the complementary color (e.g., if the reflection is set to yellow, the transmitted light is bluish).
Figure 4 : A diagram shows that complementary colors are opposite from each other on the color wheel
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