<t>update:<br/>
it does import to blender, then exporting it UE also works but it creates a collision frame around it so i cant enter the house in player mode. i think this happens in the import process when it calculates collision objects.<br/>
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i also tried opening the .obj file with open3d ...

didnt think of importing to blender, ill try it alongside with your other tip tonight. thx!

thanks for the tip, i removed all furniture and lights just leaving walls doors and windows. in the end, when saving the UE project it seems to go better but still saving crashes just at the end.

probably need to trail and error a lot to find out on which object it stubmbles.

<t>I wanted to import the sweethome3d project to unreal engine and in another thread here someone advised to first import the obj file to twinmotion.<br/>
this worked fine although the model was on its side but this was easily fixed by dragging the model 90 degrees.<br/>
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Next i saved as ...