topic Re: Unable to split or cut body in Fusion Support Forum

Unable to split or cut body

adam.demuri — Thu, 02 Dec 2021 04:06:11 GMT

I have a body which I made as follows:

- Created a surface using a form - this surface was open on one end, and closed elsewhere

- Closed the surface with a patch

- Stitched the patch to create a body

- Combined the body with another body, from a normal sketch -> extrude

The combined body has a "bump" on the bottom, which I'd like to remove, as I'm going to 3D print this object. But, when I try to cut body to remove the bump, it fails, telling me that there's no intersection between the target and the split tool. This is clearly incorrect. I've attached the file. I'm using the bottom of the angled piece as the cutting tool. I also tried inserting a plane and using that as the cutting tool, and manually drawing an area and doing an extrude cut. None of these methods worked.

Re: Unable to split or cut body

wmhazzard — Thu, 02 Dec 2021 04:39:21 GMT

I don't know why a surface or a plane won't work, even a thickened surface won't cut away the bump. I did find that creating a sketch and doing an extrude cut works in removing the bump. It could be a bug.

Re: Unable to split or cut body

jeff_strater — Thu, 02 Dec 2021 17:22:34 GMT

This looks like a bug to me. I suspect it's because of the "near equivalent" geometry beyond the bump. This is something that Split Body/Cut operations of any kind struggles with.

I'll take this up with the modeling kernel team.

BTW, that error is misleading. I think it is kind of a "catch-all" error - if we don't know why the split fails, then we show this error.

Re: Unable to split or cut body

TrippyLighting — Fri, 03 Dec 2021 00:10:22 GMT

There's a flatten tool in the T-spline/Form modeling tools that can easily flatten the bottom and remove that bulge.

Don't fix T-spline mistakes with surfacing tools when that can be so easily foxed with T-Spline tools 😉

Here is your T-Spline model in Box view mode;

Here is my version:

It is much closer to the final shape than your model. It uses no N-Gons (and no triangles, but there were none in your model anyway).

Your model stretches the control cage too much to get the shape you want. That means you need to add mode edge loops.

Re: Unable to split or cut body

jeff_strater — Fri, 03 Dec 2021 23:19:39 GMT

I hadn't realized that @TrippyLighting already mentioned the Flatten tool before I recorded this, so here it is: Peter is right - you can fix this in TSplines.

The kernel team is looking into the Split problem, as well.

Also, how did you make this TSpline? Did you import a quad mesh, or did you create it natively in Fusion?

Re: Unable to split or cut body

adam.demuri — Sat, 04 Dec 2021 16:32:22 GMT

Thanks, I did use the flatten tool to fix this - just wanted to report the bug as well. I created this shape by extruding the face of the wedge piece.

And thanks for the modeling advice - I'm new to forms, so that's helpful!