Finding the orientation of vertical elements (like ducts/pipes/cable tray)

[PerryLackowski]

I have a duct element and I can get the two endpoints from the Location Curve, but I'm looking to find the unit vectors that represent up/down/left/right of the segment so I can perform offsets or generate parallel elements. Largely I think I can use the cross product of the vertical vector (0,0,1) paired with the direction vector (p2-p1) to get the left/right vectors. Then I can pair the left/right vectors with the direction vector to get the up/down vector. However, if the duct is vertical, the location curve doesn't give me any information about the rotation of the duct, so I can't determine which direction is appropriate for an 'Up' offset. Mathematically, this is because the first cross product is zero, so the second cross product can't be determined.

Is there a parameter I should be using that can give me more information about the rotation/orientation of the duct when it's vertical?

[jeremy_tammik · Accepted solution]

Yes. You can use the connector coordinate system at the connections at the endpoints:

• https://www.revitapidocs.com/2024/9397e93e-b63f-ec7d-fa28-7a0befb68966.htm

The Z axis of the coordinate system is the normal to the plane of the connector.

Commonly, X is width and Y is height.

[PerryLackowski]

Thanks @jeremy_tammik! That's much easier than trying to calculate them myself...