topic Curvature loft - This function is not tolerant modeling compatible in Fusion Design, Validate & Document Forum

Curvature loft - This function is not tolerant modeling compatible

paypalmarcus — Fri, 07 Apr 2023 21:15:55 GMT

Hi,

I have been having lots of issues with lofting in Fusion.

I found that to loft between surfaces, I need to apply the "curvature" option to the profile I am lofting from. This works for some very simple surfaces, but once I provide a more complicated profile, I get errors...

This function is not tolerant modeling compatible

I am trying to loft from a curvy profile to a circle as shown below:

It has no problem with tangency, but then it leaves a bad indention at the surface intersection that also translates to the 3D print.

Please see the PDF for better resolution pictures. I also attached the fusion file

Re: Curvature loft - This function is not tolerant modeling compatible

jeff_strater — Fri, 07 Apr 2023 21:26:30 GMT

That is an admittedly confusing message, only really meaningful to internal people. It should be replaced with something more meaningful. I can translate. I see that this model starts with imported geometry:

"tolerant geometry" means, really, that the edges of this loop of surfaces are not precisely joined together. There are very small gaps between each surface. G2 loft cannot, apparently, work with the geometry that has these gaps in it. Unfortunately, there is no easy way to repair that imported geometry. It looks simple enough that you could probable re-create a close facsimile of it yourself using Fusion. That should work with G2 loft.

Re: Curvature loft - This function is not tolerant modeling compatible

TrippyLighting — Sat, 08 Apr 2023 11:40:24 GMT

You are using the wrong loft option!

When you are lofting with the "Keep tangent edges" disabled, Fusion 360 will try to create a curvature continuous loft. that means curvature continuous not only in the loft direction between profiles 1 and 2, but also along the circumference.

However, profile 1 has a near tangency condition at least in one place so Fusion 360 generates this warning.

If you enable the "Keep tangent edges" option the loft will work fine without the warning.

@jeff_strater "Keep tangent edges" should by all means be enabled by default!