topic Re: How do you close a T-Spline Loft? in Fusion Design, Validate & Document Forum

How do you close a T-Spline Loft?

tvollaro — Fri, 10 Jul 2015 14:25:29 GMT

Why are my T-Spline Lofts not closing when I check the Close check box? Attached is an image of two very simple lofts, one with two closed arcs and one with two closed circles. I know I can do this easily with Model or Patch, but I want to use T-splines so I can perform more sculptural shapes (see the end of the long loft.)

Re: How do you close a T-Spline Loft?

jeff_strater — Fri, 10 Jul 2015 14:39:19 GMT

Thanks for the post! I think I can explain what you are seeing. The "Closed" flag here is really for a loft that loops around on itself. What I think you want are end caps on your loft, like you would get in a solid body loft. Sculpt (TSpline) lofts today do not add end caps. You can do this using the Fill Hole command, specifying the "Maintain Crease" flag:

Hope this is helpful!

Jeff Strater (Fusion development)

Re: How do you close a T-Spline Loft?

tvollaro — Fri, 10 Jul 2015 14:52:51 GMT

Thanks Jeff!

That works well for the circle, but I get this error when trying to do that on the arc-based loft

Re: How do you close a T-Spline Loft?

Anonymous — Fri, 10 Jul 2015 17:11:12 GMT

I tried this on similar geometry, and didn't run into problems. It would be great if you could upload to this thread a .f3d export file of this problem model.

Jesse

Re: How do you close a T-Spline Loft?

tvollaro — Fri, 10 Jul 2015 17:26:36 GMT

Here is the F3D file. Thanks!

Re: How do you close a T-Spline Loft?

jeff_strater — Fri, 10 Jul 2015 17:51:36 GMT

Thanks for sharing the file.

The problem here is that there are two bodies:

Fill Hole can only apply to one body. So, you can merge the bodies using Weld Vertices, and then Crease Edge to get the sharp edge back. Then Fill Hole can work:

I've attached the fixed version of the model, just FYI.

Jeff

Re: How do you close a T-Spline Loft?

Anonymous — Fri, 10 Jul 2015 18:03:03 GMT

Ok so I noticed you extruded the arc and the bottom line as two seperate T-spline extruded bodies, so I first did two Merge Edge operations. In such an operation, for Edge group one I double clicked on the first edge segment, which selected all segments of that edge (for one body or the other not sure), then for Edge group two did the same thing (it knew to then select the edges of the other body, which ever that happened to be). I also chose to maintain crease. Did the same thing for other side. Then was able to successfully do a Fill hole, noting that the Fill star option created a simpler surface.

Unless there is some specific reason not to, I would recommend when doing such an extrude, to just select the entire closed profile to extrude in a single operation, so that such merge edge operations are not needed.

Good luck with the guitar!

Jesse

EDIT: Haha Jeff beat me to it 🙂 Interesting that both Weld vertices and Merge Edge seems to work.