OpenMaterial_emissivity_data

OpenMaterial_emissivity_data

This is a proposal for an extension to the Khronos Group glTF 2.0 specification. The goal of this extension is to provide a physically accurate description of the emissivity coefficient at a given temperature in a look-up table. Values within the range which aren't explicitly listed can be obtained using linear interpolation.

The extension may serve as a blueprint for further material-specific look-up tables referenced from the physical_properties section of the OpenMaterial_material_parameters extension.

In order to use this extension, it has to be listed in the extensionsUsed section of a corresponding material file:

"extensionsUsed" : [
    "OpenMaterial_emissivity_data"
]

Properties

This extension provides emissivity coefficient data measured at a certain temperature.

Within the following enlistment of properties specified by the proposed extension, items labeled as required are mandatory and must be present. Properties without required label are optional and may be omitted:

• temperature [number][required] Temperature [K] at which an emissivity coefficient value was measured.
• emissivity [number][required] Emissivity coefficient [-].

Example

Within the section physical_properties of its OpenMaterial_material_parameters section, a material file (e.g. aluminium.gltf) provides an URI to a emissivity coefficient data file:

"materials": [
    {
        "name": "aluminium",
        "extensions": {
            "OpenMaterial_material_parameters": {
                "user_preferences": {
                    ...
                },
                "physical_properties": {
                    ...
                    "emissive_coefficient_uri": "data/aluminium_emissivity.gltf", <======					
                    ...
                }
            }
        }
    }
],

The emissivity coefficient data file (in this case aluminium_emissivity.gltf) provides the data to compute emissivity at the geometry:

"extensions": {
	"OpenMaterial_emissivity_data": {
		"data": [
			{
				"temperature": 300.0,
				"emissivity": 0.048
			}
		]
	}
},

glTF Schema Updates

N/A

JSON Schema

OpenMaterial_emissivity_data.schema.json

Known Implementations

N/A