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asam-ev / OpenMATERIAL

3D model exchange format with physical material properties for virtual development, test and validation of automated driving.
https://asam-ev.github.io/OpenMATERIAL/
Mozilla Public License 2.0
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Add thickness parameter for transmittance calculation. #141

Open Norihito-Hiruma opened 1 week ago

Norihito-Hiruma commented 1 week ago

To calculate the attenuation of transmitted light, the thickness parameter of the material is required. The attenuation of light is calculated using Lambert-Beer's law, which requires not only the complex refractive index but also the path length inside the material. The path length of light within the material can be calculated using the refractive index and the thickness of the material, hence the need for the thickness parameter.

Attenuation calculations

lyndyRott commented 1 week ago

From my point of view this is an interesting aspect, which is very useful in sensor modeling. A model for reflection-absorption-transmission and refraction is needed and a parameter for thin-layered materials can support modeling of various detection-range and energy considerations.

This issue is related to both #126 and #122 from my point of view.

However, a material thickness parameter itself is more related to the geometry description and cannot be a material-parameter itself, I'd think. Thus, the geometry or modeling engineer (customer/user) can define a thickness t in their model or geometry and the material standard can only provide the attenuation coefficient, which is the material parameter.

As presented above, the complex index of refraction (IoR) m holds an absorption property in the imaginary part (k).
These properties are part of the volumetric description of materials.

We should definitely add an option to include the real and imaginary part of the IoR, imo.

Norihito-Hiruma commented 1 week ago

I understand that Rott-san's opinion regarding thickness information is as follows: If thickness information is held within the model, it can be utilized. If it is not available, then the thickness information within the Geometry information in the asset file can be used. Is my understanding correct? As you pointed out, thickness information is indeed part of the Geometry data. If my understanding above is correct, I think it's a good idea. It is necessary to have a mechanism in the asset file to associate information related to the shape required for sensor simulation with 3D shape components (nodes, etc.).

ClemensLinnhoff commented 6 days ago

I also agree, that thickness is a useful information, but not a material parameter. Let's discuss, if/how we can incorporate thickness (and potentially other volumetric parameters) into the asset file @LudwigFriedmann.