I get random orientation of mullions when placing a curtain system on a mass.
The mullion is not symmetrical, so I have created two versions of it.
The curtain system has defined mullion type for both vertical and horizontal border1 /2 and prove to be working on simple flat surface.
When applied to a complex mass object, I get random results. Within the same curtain system, half of it will get the correct mullions, and the rest will have border1 default mullion instead of border2...
The mass I have been applying the sytem to, is a very long band of windows shifting from vertical to horizontal. I noticed that mullions get shifted depending on the angle of the panels.
Mullions can be changed manually, but we're talking about a thousand mullions here. so I would rather not do it that way.
NB : the mass family contains a sat import from Rhino. I did experience similar issues doing test with mass family created only in Revit, so I don't think it has to do with the Rhino export. Faces have both in Rhino and Revit the correct orientation.