Did you create this door frame yourself by saving slabs as a door object?
If so you forgot to add a slab to represent the arched wall hole (i.e. an arched shaped slab with an ID of WALLHOLE).
https://helpcenter.graphisoft.com/knowledgebase/25570/
If it is not an object you have created, what object is it?
Barry.
One of the forum moderators.
Versions 6.5 to 27
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