SceneQuads are computed 2D primitives that describe a flat surface and has an API designed to be used to help placement of the objects.
When using the triangle mesh from Spatial Map to perform placement, one had to scan all areas of the quad and perform hole filling/post-processing to identify good locations for object placement. This is not always necessary with Quads, as the Scene understanding runtime is capable of inferring which areas of the quad that were not scanned, and invalidate areas of the quad that are not part of the surface.
{% hint style="danger" %} Note that Scene Understanding SDK is only available for HoloLens 2. {% endhint %}
If your application intends to place 2D or 3D holograms on rigid structures of your environment, the simplicity and convenience of SceneQuads for placement is preferable to computing this information from the spatial mapping mesh.