inconsistent face edge relationship when trying to cut a body

[joel.a.loikkanen]

I am making ribs for my airplane wing. My approach is copying the lofted wing, cutting it up into ribs, then combining the wing and the ribs. It worked fine with less ribs, however as I added double the amount of ribs into the original sketch, the method stopped working. I've also tried cutting up the rib body with split body and the sketch, as well as projecting the sketch on to the body with no luck. I'm out of ideas, why can't I cut through the body? The files and screenshots are attached. 

[davebYYPCU]

Can check the file tomorrow, but are you cutting one wing or original / copy - both at the same time?

check the cutting sketch for duplicate / overlapping curves.

Might help....

[joel.a.loikkanen]

Thank you for the reply.

I was trying to cut a scaled down version of the original wing. The same scaled down version was used to cut the wing hollow. I thought that this way the outside of the ribs and the inside of the hollow wing would line up. Your comment gave me the idea of making a copy of the wing without scaling it down and then making the ribs from that. Surprisingly, that worked beautifully!

For future reference, do you have any ideas why i couldn't cut the scaled down version of the wing?

[davebYYPCU]

I had a look at the file, I can't explain the error, it normally happens with duplicate sketch curves or duplicate bodies to cut, but you don't have either.  Can only presume the scaled body is the reason, because I was not able to split the body with your curves either.

Good that you have progressed around it.

[jeff_strater · Accepted solution]

oftentimes, that error (which is not very helpful, certainly...) indicates that there is "near equivalent" geometry that you are trying to Combine (join or cut).  So, two faces that are almost, but not quite exactly on top of each other.  Simple surface geometry like planes and cylinders are usually immune to this, but if you have any complex spline surfaces in your model, this error can occur.  And, it can be exacerbated by scale.  Say you had two surfaces that started out as the same (as a Copy Body, for instance), and maybe one was trimmed away, then both were scaled (by exactly the same amount, even), the numerical differences between the two resulting surfaces can be enough to trigger this error.  Disclosure, I have not even looked at your design yet....

[TrippyLighting · Accepted solution]

I have looked at the model and don't see good reasons this should not work.

The wing profiles are created from straight lofts between closed fit-point splines with 6 control points.

The Cutting profiles are arcs.

Extruding one of them and trying a splint body operation also returns an error Clearly there IS and intersection.

Edit, some more experimentation indicates that the trailing edge is the problem.