Failed to boolean bodies together - joining two bodies that intersect

[caryjor]

I'm stumped.  I'm designing an exhaust manifold.  it's two halves.  The way its modeled, its quickest/easiest for me to model one side of the exhaust, mirror it, then join the bodies.  THis worked perfectly fine on the bottom half of the manifold.  On the top hald, I get the "Failed to boolean bodies together" error when combining no matter what I do.  I've tried extending the mating surfaces to creat overlap, tried slicing the pieces so they only join on one axis, tried joining during the mirror then joining to the remaining outlet piece.  Nothing works.  

Here are the two bodies I'm combining:

Here's how it should look combined. 

As you can see, the pieces connect.  The little piece was sliced out of the main piece and mirrored.  It was sliced on the plane and mirrored on the same plane. 

This worked fine on the lower half of the manifold:

Any help is appreciated.

[jhackney1972]

The Forum really needs your model to do anything.  

If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section, of a forum post, to attach it. If needed, ZIP a F3Z file.

[caryjor]

John,

Id love to attach it but I’m a bit hesitant as this is a proprietary model for a part I plan to manufacture/sell. This honestly seems like a pretty deep rooted bug in fusion.  Is there any way to diagnose without the model?

[TheCADWhisperer]

@caryjor 

Before attempting the Combine - does Ctrl b (CMD b on Mac) return any errors.

[caryjor]

no errors.  no issues in timeline either

[jhackney1972]

I would try moving one body a small amount toward the other body to be sure they are intersecting.  You could also add material to one of the bodies to make sure they intersect.

[caryjor]

Thanks! Yes, I’ve tried both of these. I’ve added material at both areas the bodies touch. I tried moving the bodies also. Same error

[TheCADWhisperer]

@caryjor 

Try going into Surfaces and Deleting some surfaces, then Stitch the boundaries.

[jeff_strater]

Most Boolean errors come from "near equivalent" surfaces (usually spline surfaces) on the bodies where they touch.  Those are surfaces that are very similar, but differ just slightly, sometimes in ways you cannot even see by looking at them.  If you are trying to combine those two faces, there may be overlaps or gaps that are too small to see (at machine precision), but wreak havoc with the code that is trying to produce one body.  If you are truly unwilling to share the model, the best that I can recommend is a "divide and conquer" approach.  Temporarily (or in a copy of the design) split the bodies, Remove half of each, and if the Combine succeeds, then you know that the problem surfaces are in the halves that your Remove.  Undo, try moving the split plane, or add other split planes, until you narrow down the problem geometry (it could be just one set of faces, or more than that).  Once you identify those faces, see if you can make some modifications that will make it succeed.  If you are willing to share it with us, we can save you a lot of time.  We'd also like the model as a future test case, if possible...

[Drewpan]

Hi,

What did you use as your Mirror Line? Sometimes the mirror command works

just fine but I have noticed that sometimes there can also be the tiniest gap

that fusion sees but you can't.

What does fusion say if you use the Interference command?

If they are not touching they will not join. A common failure is when they are

so close for all intents and purposes they are touching but fusion does not

actually detect it. A La my first comment.

Not a real solution but what happens if you try to put a Rigid Joint between

the components instead?

Cheers

Andrew

[TrippyLighting]

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@caryjor wrote:

John,

Id love to attach it but I’m a bit hesitant as this is a proprietary model for a part I plan to manufacture/sell.

---

In that case, you should contact official Fusion support. This is a public forum and debugging a model, or reporting a bug is not feasible without the model on hand!

I have tagged an Autodesk employee but that doesn't guarantee a timely response.

@johnsonshiue 

[johnsonshiue]

Hi @caryjor,

One quick test you could try is to edit the Stitch features. Try tightening up the tolerance to 0.00001mm. Does it work better?

As Jeff and other experts already mentioned, it will be very helpful to us if you can share the file with us. Boolean errors can be caused by many things. The images don't help us understand the issue better.

Many thanks!