Revit Dynamo Error : COINCIDENT_REGION

Have anyone seen this error before ?

It’s said “One or more geometries have failed to convert due to this error: Failed to trim surface with polycurve loops. : COINCIDENT_REGION – There are two curves with coincident regions”

I just try to search for Stairs - Runs or Stairs - Landings from Revit file and convert it to geometry but turns out it’s error as you can see on screenshot.

How can I solve this problem ?

Sounds like you have overlapping objects somewhere. Lookup the elements with failed geometry by ElementId and see if you can find any similarities or model issues.




As I checked the issues, there’s nothing wrong with it. It’s just a Stairs - Runs model in the group, with nothing overlapping (see Pic. 3, which shows a graphic confirming no overlapping of the Stairs - Runs model). In Pic. 4, I tried deleting the Stairs - Runs model, and it disappeared with nothing underneath it.

Is geometry scaling set to medium?

Yes, it is.

Can you open detached, remove everything other than that stair (all but one 3d view, all materials and material assets, every other modeled element, all levels except those required to generate the stair, all grids, etc.), and post the .rvt to the Dynamo GitHub or here so that we can get the development team to take a look?

Thank for reply and your help!. Here’s the Revit file and Dynamo file.

Dynamo_Coincident-Region_Test.rvt (4.4 MB)
Dynamo_Coincident-Region_Test.dyn (5.2 KB)

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The way your landing is joining the second run in the sequence isn’t valid for the Dynamo geometry engine. Revit can’t work with small stuff (as we all know) so it discards a lot of stuff which other geometry engines would have issue with. In this case Dynamo is having issues making the connection between the 2nd landing and the 2nd stair, as the stair run terminates a riser below the landing. Revit’s doing some geometry shortcuts to apply a riser there, but the shortcut is not a valid solid as it self intersects resulting in a surface which overlaps itself.

To fix this, modify the stair landing and run. Extend the run by one riser, and modify the landing to be L shaped around the top of the stair. Most of your stairs were built this way, but the failing instances were not.

Dynamo_Coincident-Region_Test.rvt (4.6 MB)

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Thank you for your help. But what about this one?

It’s from the same Revit file. These stairs were created using the same method, family, and type. However, one group shows an error in Dynamo, while the other doesn’t. I’m not sure why this is happening.


Dynamo_Coincident-Region_Test02.rvt (2.7 MB)
Dynamo_Coincident-Region_Test.dyn (5.2 KB)

Same problem as above. The landing needs to be reshaped to ensure consistent clean results.

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Then why doesn’t the other one have an issue? Sorry for asking, but I’m just curious.

It’s a function of the fraction of a fraction of a mm which Revit rounds away, but Dynamo cannot. If you shift around the stair oh so slightly it’ll go away, but the capability to do so in the 3d space without doing your design is far more difficult than editing the stair.

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