AccessibilityAPI

This schema describes accessibility information on a Prim that may be surfaced to a given runtime’s accessibility frameworks. This information may be used by assistive tooling such as voice controls or screen readers.

Accessibility information is provided as a standard triplet of label, description, and priority.

def Mesh "Cube" (
    prepend apiSchemas = ["AccessibilityAPI:default"]
) {
    string accessibility:default:label = "Luxo, Jr"
    string accessibility:default:description = """The lamp has round base with 
two sections above it that may be adjusted. It has a conical head with a 
lightbulb inside. It likes to chase inflatable balls."""
    token accessibility:default:priority = "standard"
}

This is a multiple apply schema, and so may have multiple namespaced accessibility triplets, where an instance name may reflect a given purpose for that triplet. For example, you may desire to express different information for different aspects of the prim, such as size or color.

There are several best practices for using this schema:

Most accessibility runtimes support a single accessibility description. Therefore we recommend using a namespace labeled “default” for any critical information.
A default value should be authored if using time sampled accessibility information. This helps accessibility runtimes that do not currently support time sampled information.
Provide accessibility information of your scene on the default prim of the layer, and any root level prims. This allows accessibility systems to provide concise scene descriptions to a user, but also allows supporting accessibility systems that either do not support hierarchy information or when a user has turned off that level of granularity. Accessibility information may still be provided on other prims in the hierarchy.

The use of the default prim and root level prims for scene accessibility descriptions is a recommended convention. Outside of that, accessibility information is not implicitly inherited through a prim hierarchy.

Properties

Properties

description

USD type: string

An extended description of the prim to provide more details. If a label attribute is not authored in a given instance name, the description attribute should not be used in it its place. A description is an optional attribute, and some accessibility systems may only use the label.

Descriptions may be time varying for runtimes that support it. For example, you may describe what a character is doing at a given time.

label

USD type: string

A short label to concisely describe the prim. It is not recommended to time vary the label unless the concise description changes substantially.

There is no specific suggested length for the label, but it is recommended to keep it succinct.

priority

USD type: token

Fallback value: standard

A hint to the accessibility runtime of how to prioritize this instance’s label and description, relative to others. Allowed tokens are “low”, “standard”, and “high”.

This attribute is optional and is considered a hint that runtimes may ignore.

Priority may not be time varying.