Behaviour of a referenced scalable Reality Mesh (.3sm format) is slightly different from most other elements. As the mesh is scalable the length and position of individual mesh edges is not fixed like a conventional mesh; these edges are not represented by conventional vector lines that have start/end/midpoint etc., they behave like strings of points.
Intersection snap mode cannot work with these representations as, unlike a conventional mesh, there are no intersecting (directional vector) lines.
Keypoint, Nearest, Midpoint, Bisector, Centre and Origin snap modes will all snap to a Reality Mesh but will appear to have identical behaviour; as they are snapping to points, not vectors, the snap location will be coincident for all of these snap modes.
Other snap modes are geometrically incompatible with Reality Mesh so display a warning symbol:
When attached a Reality Mesh Element has the Unlit Smooth Display Style applied (to the element). The element Display Style overrides the active view Display Style so the textures will be displayed
To be able to snap to the mesh the User Preference > Input > Locate Interiors option must be set to either Visible or Always. This allows snapping to locate any point on the mesh surface. This is the most appropriate mode when attempting to locate new elements relative to the mesh.
The exception to this is if the Wireframe Display Style is applied; snapping will then locate any of the points that make up the displayed mesh.
AECOsim users: Please note that the default setting for the 'Locate Interiors' option in our delivered preferences is 'Never'. This should be changed when working with Reality Meshes where the element display style is other than Wireframe.