8.4 Material optical schema

8.4.1 Overview

This is the documentation about the JSON schema file. The actual file is located in the ASAM OpenMATERIAL 3D GitHub repository.

The following diagram shows the hierarchy of the fields defined in this schema. Fields marked with (R) are required. A field can be optional while some of its children are required. In that case, the required children only have to be filled in if the optional parent field is present.

8.4.2 metadata

The key meta information about the optical look-up table.

Type: object
Required: Yes

8.4.2.1 name

The display name of the material, such as 'Red brick' or 'Dark asphalt'.

Type: string
Required: Yes

8.4.2.2 description

Short description of the material in two to three sentences.

Type: string
Required: No

8.4.2.3 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

8.4.2.4 materialVersion

The version number of the material, following semantic versioning (for example, '1.0.0').

Type: string
Pattern: ^\d+\.\d+\.\d+$
Required: Yes

8.4.2.5 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

8.4.2.6 copyrights

Type: array
Item count: at least 1
Item type: string
Required: Yes

8.4.2.7 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

8.4.2.8 authors

Lists the author(s) of the material as a name, email, or company.

Type: array
Item count: at least 1
Item type: string
Required: Yes

8.4.2.9 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: No

8.4.2.10 sources

Sources of the optical property data. Was it measured, simulated, or taken from literature? Multiple sources should be comma-separated.

Type: string
Required: Yes

8.4.3 opticalProperties

Type: array
Required: Yes

Array of optical property values, with each item representing a different property. The array shall be sorted based on the columns starting with the first.

Column count: exactly 4

Columns of the table:

Column Type Constraints Description

Column	Type	Constraints	Description
1	number or null	`[1e-09, 0.01716]`	Wavelength of the radiation in free space. Unit: meter (m). The upper limit corresponds to 20 kHz.
2	number or null	`[0, inf[`	Temperature of the material. Unit: kelvin (K).
3	number or null	`[0, inf[`	Real part of index of refraction of the material, which is \(n^{'}\) in \(n = n^{'} - j \kappa\).
4	number or null	`[0, inf[`	Imaginary part of index of refraction of the material, which is \(\kappa\) in \(n = n^{'} - j \kappa\).

number or null

[1e-09, 0.01716]

Wavelength of the radiation in free space. Unit: meter (m). The upper limit corresponds to 20 kHz.

number or null

[0, inf[

Temperature of the material. Unit: kelvin (K).

number or null

[0, inf[

Real part of index of refraction of the material, which is $n^{'}$ in $n = n^{'} - j \kappa$.

number or null

[0, inf[

Imaginary part of index of refraction of the material, which is $\kappa$ in $n = n^{'} - j \kappa$.