I can confirm the 2D preview of those "RM" objects is incorrect.
I can't see why though.
The "RM" (Roof Maker" objects are different to the standard roof timbers in the library.
They have the ability to be angled, the standard object does not.
If you do have the "RM' pulins on an angle, you will also want the 'Structural Length' and not the 'Horizontal Length'.
The standard purlin does not have a structural length parameter (it is always horizontal so just length is fine).
I don't have any idea why the 2D preview of the RM objects is wrong.
I would report this to your local support to see what they say.
One of the forum moderators.
Versions 6.5 to 25
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