Loft self intersecting body

graham_lock

Hi,

I'm having trouble with what I would expect to be a simple loft, having said that I don't have much Onshape experience.

The loft is 'Sheeting upper' on the 'Outer wing panel' tab.

I've experimented with guides and connections but so far to no avail.

The document link is:
https://cad.onshape.com/documents/58e03e2b96e2c78f575caefc/w/4810d8adb3591ae247e67c57/e/efc80ac549423a84abb0a9db

Any help appreciated.

S1mon

I can't quite tell what you were trying to do in a single loft which was failing, but a typical issue is that lofts can't have inner voids.

If you didn't have inner voids, perhaps you had multiple regions within each sketch, and it was having a difficult time with that?

Here's a simple loft which works fine without any guides or connections:

Notice that Sketch 1 and 2 have the same number of elements, and each is a single face. Loft can manage that easily. It can handle multiple connected faces (see second example), but if they get too complex, the connections can get crazy.

Sometimes when you're trying to resolve problems like this, it can help to create a really simple examples, and see where things break.

graham_lock

So I've solved this by breaking the loft selections into smaller profiles.

I'd be interested in understanding why this is necessary?

Thanks.

S1mon

I can't quite tell what you were trying to do in a single loft which was failing, but a typical issue is that lofts can't have inner voids.

If you didn't have inner voids, perhaps you had multiple regions within each sketch, and it was having a difficult time with that?

Here's a simple loft which works fine without any guides or connections:

Notice that Sketch 1 and 2 have the same number of elements, and each is a single face. Loft can manage that easily. It can handle multiple connected faces (see second example), but if they get too complex, the connections can get crazy.

Sometimes when you're trying to resolve problems like this, it can help to create a really simple examples, and see where things break.

graham_lock

Thank you for the examples and advice.

I'll try the simple example route going forwards.