Hello, I have a group type loaded into Revit project, I use “add model group” to place multiple instances of this group into the model. Different locations and rotations (using rotated XY planes) is not a problem. Problem emerges when I try to place instance that is mirrored. To do that I have tried flipping axis of a plane that goes into “Point” input of the component. When I do that I get the error: “Element cannot be mirrored or rotated in a manner that changes its angle relative to the ground”. If I mirror same group instance inside revit everything works fine. Is there a way to place group instances mirrored?
Hello Muhammad, thank you for reaching out. I followed your suggestion and tried using “Element Location” but when trying to set a flipped plane I get the same error (see image attached).
I also attach two files - Revit with two groups and a script where you can switch between not flipped and flipped planes when placing Group Instances.
Groups contain couple of walls, rooms and a floor.
Please let me know if you found a way how to deal with that
MirrorTest-GROUPS_forums.rvt (14.9 MB)
MirrorTest-GROUPS.gh (13.6 KB)
Hi @WR_QU
I am unbale to open the file. I think you are using Rvt 2026.
Muhammad, yes it was created in 2026. Which version are you using?
I am using 2025.4
I am sorry for getting back late, I needed to find someone in the office with this version. Below I upload the 2025.4 revit file together with RiR grasshopper script:
Mirror_test_group_forums.rvt (10.1 MB)
MirrorTest-GROUPS.gh (13.6 KB)
@WR_QU, I believe that’s because of walls as they vertical elements constrained by the level and cannot be flipped or mirrored in a way that would change their angle relative to the horizontal ground plane.
I did a small test to check. its working for other groups as expected
Thank you for your tests and reply. That is a bit surprising for me - I can very easily mirror the same group in native Revit (MM or DM) without any errors, but when I try to place a mirrored group via RiR I get the error.
Yes you are right it works in Revit. Let me check it again if we have any information available in API
Sorry, I missed this post. What you showed in the first picture is exactly what I was after. I cannot get there no matter how many times I run the definition (always same error). Is there any specific order of things I should do to get there (other than recompute)?
nothing it just change the view from 3d to plan view
@WR_QU There is some issue with this model group. I would recommend rotating the model group instead of just flipping the plane.
Unfortunately, I need it mirrored, not rotated. These are just basic revit elements inside the group, nothing special. Thank you for trying to help though. @Japhy maybe you would be able to help here?
Would that be ok if we mirror the group using after placing them.
1 Like
Muhammad, I wanted to omit mirroring after placing groups but that will work. Thank you once again
You can simply select the element and provide the mirror plane.