8.6 Material reflection coefficient schema
8.6.1 metadata
Metadata about the material.
Type: object
Required: Yes
8.6.1.1 name
The display name of the material, such as 'Red brick' or 'Dark asphalt'.
Type: string
Required: Yes
8.6.1.2 description
Short description of the material in 2 - 3 sentences.
Type: string
Required: Yes
8.6.1.3 uuid
Universally unique identifier for the material in 8-4-4-4-12 format, see [12]. The uuid stays the same, even if version is updated.
Type: string
Pattern: \\b[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\\b$
Required: Yes
8.6.1.4 materialVersion
The version number of the material, following semantic versioning (for example, '1.0.0').
Type: string
Pattern: ^\\d+\\.\\d+\\.\\d+$
Required: Yes
8.6.1.5 openMaterial3dVersion
The version of the ASAM OpenMATERIAL 3D specification used, adhering to semantic versioning (for example, '1.0.0').
Type: string
Pattern: ^\\d+\\.\\d+\\.\\d+$
Required: Yes
8.6.1.6 copyrights
Indicates copyright details, including the year and copyright holder (e.g., '© 2024 ACME Inc.').
Type: array
Required: Yes
8.6.1.7 license
Describes the license for material distribution. Use an SPDX identifier for open-source licenses (for example, 'MIT'), or provide a URL or filename for proprietary licenses.
Type: string
Required: Yes
8.6.1.8 authors
Lists the author(s) of the material as a name, email, or company.
Type: array
Required: Yes
8.6.1.9 creationDate
The date and time of material creation, formatted as YYYYMMDDTHHMMSSZ according to ISO 8601 [8] (for example, '20240703T101728Z').
Type: string
Pattern: ^\\d{8}T\\d{6}Z$
Required: Yes
8.6.2 reflectionCoefficient
Reflection coefficient lookup table including relevant meta data. The reflection coefficient is defined as the ratio of amplitudes of the reflected electromagnetic wave over the incident electromagnetic wave \(r = E_{\textrm{r}} / E_{\textrm{i}}\). This complex value is represented by angle- and wavelength-dependent magnitude and phase values.
Type: object
Required: Yes
8.6.2.1 wavelengths
List of all wavelengths in meters contained in the lookup table. The wavelength values shall be within the range of 1e-09 to 17.16e-03 (upper limit corresponds to 20 kHz).
Type: array
Required: Yes
8.6.2.2 lookupTable
Array of reflection coefficient values, with each item representing a different property. The array shall be sorted based on the columns starting with the first.
Type: array
Required: Yes
Columns of the table:
-
Column 1: Wavelength of radiation in free-space in meters (m). The value shall be within the range of 1e-09 to 17.16e-03 (upper limit corresponds to 20 kHz).
-
Column 2: Incident zenith angle relative to the surface normal in rad. It shall be within a range of \(0\) to \(\pi/2\).
-
Column 3: Exit zenith angle relative to the surface normal in rad. It shall be within a range of \(0\) to \(\pi/2\).
-
Column 4: Exit azimuth angle in rad. It shall be within a range of \(0\) to \(2 \pi\). The value is relative to the incident azimuth angle. The incident azimuth angle is set to 0° as the incident ray is used as reference.
-
Column 5: Polarized plane angle in rad. This is the angle between the plane containing the incident, exit, and normal vector, and the plane of polarization. The plane of polarization contains the direction of propagation and the electric vector. The value shall be within a range of \(0\) to \(\pi\).
-
Column 6: Magnitude within the linearly polarized plane. The magnitude is given as an absolute relative value compared to an ideal reflector. The value shall be between 0 and 1
-
Column 7: Phase within the linearly polarized plane. It shall be within a range of \(-\pi\) to \(\pi\). If the phase is not taken into account, it is null.