Sweep Cut Can't Self Intersect - Why? Intended Behavior or Bug?

[dtroy15]

I need to use a sweep cut to create a relatively complex compound-curve surface for a hydrodynamic application. In attempting to do so, Fusion stops the operation and throws an error for a self intersecting body. I understand why a self-intersecting sweep could be problematic when creating a body. However, I don't understand why this self-intersecting sweep CUT won't work? Such a cut does not produce any impossible geometry to model or manufacture. So why can't I make this sweep cut?

I've attached an example file (separate from the part I am working on) which shows this issue.

[g-andresen]

Hi,

Please show a picture of a real object.

günther

[TheCADWhisperer]

@dtroy15 

What are you attempting to model?

Experienced users tend to not use Primitives (Cylinder).

Your Hole1 appears to be at a random location?

Your Hole2 appears to be at a random location?

The circle in your Sketch4 is not dimensioned and appears to be a random size?

The circle in your Sketch4 is not perpendicular to the start of the Sweep Path?

I thought this one would be trivially simple to resolve - but after examining your file - I have found the true Design Intent to be ambiguous.  I am still certain there is a simple solution but the Design Intent must be better understood.

You have Attached image rather than use the camera glyph to embed the image which makes it just a bit harder for anyone wanting to help...

[jeff_strater]

"I understand why a self-intersecting sweep could be problematic when creating a body. However, I don't understand why this self-intersecting sweep CUT won't work?"

The short answer is:  Because the steps involved in a sweep cut are:

1. build the body produced by the sweep
2. subtract it from the intersecting body

Step 1 is the same as building a new body.

The geometry kernel just does not allow self-intersecting geometry to be created