Failed to extrude sections, check input.

aaron_hearn

Im making a keychain for a friend, and when I try and extrude the highlighted piece it tells me to check input, how do i get this to extrude?

john_mcclary

hard to tell from a screen shot, for better help it is always best to link your document.

But I would assume the two stars on the top of the C's curve are exactly touching the edge of the curve. This may be creating a zero-thickness edge.
Try sliding the stars down slightly using transform and see if that works.
(or make those two stars construction lines so they are ignored for now)

NeilCooke

It will be the stars at the top that touch the edge of the logo - they are creating non-manifold edges (you don't want to know, other than this condition is not allowed). Move them slightly in the sketch so that they either keep or remove a small amount of geometry and it should be OK.

andrew_kleinert

I came across a similar problem. 

It was complex geometry that was triggered by a variable change.  Suddenly my parts became a sea of red "Boolean Operation failed to return a valid part" for no obvious reason.  A bunch of time was spent pulling the design apart to deconstruct what was going on, googling lots, a bit of learning about what "non-manifold edges" are before I figured it out. 

I have reconstructed a very simple instance of the problem below ...



Link to doc: https://cad.onshape.com/documents/1e38feb1afe46c1dc690dff0/w/029a649ba1e9e14491d9f344/e/0d748252251589fca813f209?renderMode=0&uiState=620af2609861fd1f00fd2869


@NeilCooke , a few questions about this ... 

The system doesn't seem to be very helpful:  "<Tree item> did not regenerate properly:  Boolean operation failed to return a valid part" isn't a helpful error message for something that is physically realisable (within tolerance).  Plus there appears to be a lot more coloured red than needs to be (should it only be the singular non-manifest edge that is indicated red?) - and this gets a lot worse very quickly for more complex shapes. 

... Should I raise an improvement request?  If so, should it be "Fix non-manifold edge / point handling in renderer"? or "Improve UX around non-manifold edges / point errors"? or something else?

S1mon

This is a fundamental issue with the Parasolid Kernel that Onshape, Solidworks, NX, and countless other systems use. You basically can't have two bodies join at a line. There needs to be some small amount of overlap.

Nic_J

I believe you must move the starts connecting with the highlighted piece. They're what stop the extrude from happening.

andrew_kleinert

S1mon said:

This is a fundamental issue with the Parasolid Kernel that Onshape, Solidworks, NX, and countless other systems use. You basically can't have two bodies join at a line. There needs to be some small amount of overlap.

Thanks for this 👍

I do wonder if the CAD system is able to be more helpful though?  Does the parasolid kernel return error details that can be of more help to the user?

The example I posted above is a fairly simple and a more obvious one.  But when the design is more complex, and the issue arises from a variable change, it can be frustratingly difficult to figure out what is going on (well, it is for me anyway 😀)

Anyway, this is all in the spirit of continual improvement - I’m not complaining.