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What if the Project 3D Elements results does not form a closed curve?


New member
Hi everyone,

As I want to measure a frontal area for drag coefficient calculation, I google it and I got this link:

I follow his instruction, but unfortunately, I form a not closed one. I have try to connect them point by point by splines but does not success.

Could you tell me what should I do? I attach pictures here for your reference.



Super Moderator
Project other surfaces where there are gaps, or add a line between the endpoints. You might have to delete projections that don't make sense. Depending on the desired accuracy of the measurement, you might have to "fake" some sections.
Last edited:


New member
Dear Mr. CATIA,

Thank you for your support, I still cannot form a frontal area that looks reasonable. But never mind, it is just my curiosity. Maybe because of this difficulty, the terms drag area (= drag coefficient x area) is more common and useful. Thank you very much.