Product(s):	OpenBuildings Designer
	Version(s):	CONNECT Edition
	Area:	Drawing Views

Problem

We have two drawings that are attached as references to a master drawing model, with the architectural plan acting as a background for the mechanical plan. If the drawing is set to Dynamic mode then the mechanical objects correctly hide the architectural objects as expected.  But when the drawing is set to Cached, regardless of which order we set the Reference Update Sequence the cached geometry from the mechanical drawing will not hide the architectural geometry. 

Solution

In dynamic mode the Update Sequence will control which reference's geometry displays over the other, since the two are displayed together dynamically. However, when this single drawing model is cached, the geometry from each reference attachment is cached independent of the other. Therefore, the hidden edge calculations are carried out in two separate passes, generating two sets of linear elements, and then combined together after the fact. And since cached geometry is always composed of individual segments and not enclosed regions, the cached geometry from one reference cannot "hide" the geometry from the other reference. On the other hand, when a drawing is generated from a 3D model and the results cached, the hidden geometry remains hidden because all of the visible edge calculations are carried out in one pass.

If your project cannot accommodate this workflow an alternative method to achieve one drawing hiding the contents of the other is shown in the attached video:
1. Use the Copy/Hide Cached Geometry command
2. Create Regions from that geometry
3. Change the active display style to suit

 

For more information about the Copy/Hide Cached Geometry command see this wiki