1. Question:
1.1. A user reports that using the Revit section box causes materials to disappear when stopping and starting LiveSync again. In other words, Lumion 'forgets' the Materials outside the box after resyncing.
2. Standard Reply:
2.1: Answer:
What happens is that LiveSync, after stopping and resuming the connection, considers the geometry that is now visible as a completely new element, therefore 'forgetting' the original Material Assignment.
It's not that Lumion erases the Material assignments. It's simply that LiveSync, after a restart, detects the newly visible element as new geometry. It will not remember that element's previous Material since it is a new session, and the element was not visible when that new session was started.
Note that it's not just the Section Box in Revit, that also happens with other 3d software. For example, the same happens in AutoCAD if you use a section plane.
3. Cause/Background information:
3.1: References:
https://lumion.zendesk.com/agent/tickets/32291
https://lumion.zendesk.com/agent/tickets/40146