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Converting a self-intersecting surface into a solid

Message 1 of 4
158 Views, 3 Replies

Converting a self-intersecting surface into a solid

Given the following surface, built using a closed path and a sweep profile,

Screenshot 2023-08-26 at 5.48.59 PM.png


there will be a self-intersecting surface:

Screenshot 2023-08-26 at 5.49.10 PM.png

Screenshot 2023-08-26 at 5.49.21 PM.png


A simple patching of the upper side works, but fails on the lower edge since it is self-intersecting. My goal is to build a solid body; what can I do?


For context, this is a contrived example to demonstrate my goal of building a volcano-like tapering of the sides of random sketch shapes. It is worth mentioning that I have tried to use a loft operation with an intermediate offset of the sketch shape, but got some weird behaviour. It would seem like this would be rather straight forward to implement, but I am new to CAD, in general, and F360, in particular.


FWIW, here's the link to the design:


Labels (2)
Message 2 of 4
in reply to: ahmed3ZMZE

That cannot be done without creating interior surfaces, which will likely lead to continued modeling problems.

The boundary fill tool can create a solid, but if you use the section view tool in the inspect menu, you'll find that you have interior geometry, which should not be the case.



A loft to a 2nd profile is definitely the right tool.


Peter Doering
Message 3 of 4
in reply to: TrippyLighting

Fair enough @TrippyLighting , but wouldn't then make sense for this loft functionality to work consistently across the profile? Why is there a "crease" in the resulting solid?

Screenshot 2023-08-26 at 11.29.11 PM.png


Am I missing something or is this a bug?

Message 4 of 4
in reply to: ahmed3ZMZE

Seems that the "Direction" option for the profile option in the loft dialog helps and even precludes the need for an intermediate (middle) profile in this case. However, with a slightly more elaborate base profile (the one that defines the "volcano mouth" shape), self-intersection happens for some reason. I will follow up on this as soon as I get your feedback. I appreciate it in advance!

P.S. Rhino 7 has a much more predictable loft behaviour and I have as much experience in it as in F360.

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