Picking support

[lilleyse]

Implement raycast picking similar to Cesium for Unreal / Unity so that it's possible to do things like click an OSM building and view its metadata.

Requires physics support first: #153.

[timoore]

Taking a look at this and noting that it depends on #153 . Do you see using CesiumGS/cesium-native#777 as an alternative?

[lilleyse]

Do you see using CesiumGS/cesium-native#777 as an alternative?

Potentially. We should check out omni.kit.raycast.query first which doesn't depend on physics. Not sure if it works with Fabric yet.

[lilleyse]

Raycasting request from the forum: https://community.cesium.com/t/ground-detection-in-cesium-for-omniverse/29819/2

[lilleyse]

@timoore do you know if the ray cast query returns the path of the Fabric prim? If it doesn't we'll likely need to postpone this feature until that capability is supported.

[timoore]

@timoore do you know if the ray cast query returns the path of the Fabric prim? If it doesn't we'll likely need to postpone this feature until that capability is supported.

The raycast query result has properties for get_target_usd_path, instance_id, and primitive_id. I don't know if that is all completely specific to USD or would return sensible results for a Fabric prim.

[lilleyse]

A related feature request: get the position of the clicked point (or closest vertex) and provide it back to the user as longitude/latitude/height.