Unwanted twisted loft in Patch

[jean.medicomp]

Hello,

After making two patch sufaces, I make a loft of them.

I can't solve the places where the loft are twisted.

I've tried to solve this trouble with Form environment, but I gave up because the software take too times and finally crash too often trying to solved the geometry (too many faces, I think).

I've tried a lot of things but not the good one ... 😞

Any ideas ?

[Marco.Takx · Accepted solution]

Hi @jean.medicomp,

Is this what you want.

I used Guide Rails 

See attachment.

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[jean.medicomp]

Hi,

It's exactly that I want but could you explain (screencast if you have time) how you draw the lines between the two shapes because I have this idea but can't make it real. (Was unable to draw the line on the edges)

Sorry, I'm very young with Fusion 360, and my question could be simplistics ...

Best Regards.

[Marco.Takx · Accepted solution]

Hi @jean.medicomp,

I can't do a screencast at the moment but what I did was:

1. creating a sketch.
2. Turned on 3D Sketch in the Sketch Panel.
3. Then draw the lines (The guide rails).
4. Stopped the sketch and created the loft.

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[TrippyLighting]

The reason Fusion 360 has such a problem with your geometry is because the underlying sketches already exhibit these problems.

The sketches are comprised of nearly tangential arcs and this gets Fusion 360 close to the breaking point. Near tangency is a real problem for the geometric modeling kernel used in Fusion 360 (and Autodesk Inventor).

A much better method would be to re-trace the letters using Splines with as few spline control points as you can get away with Ising the spline handles. Or you can try the new CV splines.

This will result in much cleaner geometry that is also much easier to loft and won't have as many problems down the (modeling) line.

[jean.medicomp]

Hi,

Your technical explaination is clear, but for me, the trouble and solution aren't good.

I've reduce my design to one letter, just because more letters egual much more troubles ...

I can't imagine have to re-trace all letters of a long text, and sure I'm not alone in this case ...

Best Regards.

[TrippyLighting]

No you certainly are not alone in this and I understand the pain involved the using text objects.

The fonts that are used in Fusion 360 are "just" standard fonts and for some applications they work, but there are limits. They were never de eloped to be used in such a way, and thus they don't have any curvature continuity, which is the problem.

The technique @Marco.Takx has posted might well get you to where you want to be so try how far you can push that.

The S-Letter even filleted and that might be all you want to do with it.

IF there are individual letters that create a problem, then retrace just these letters. The intention behind my post was to explain what the root cause of the problem so you are armed with knowledge that might help you solve problems on your own 😉

[jean.medicomp]

Unfortunately it's not only one letter where the trouble is present. And sometimes, it's totally un-usable ... Just try to make same thing an "a" and you'll see.

I don't know if these fonctionnalities has been developed to be used in a particular way, but you can't prevent people trying  to use a tool for their needs.

Don't forget that Human has always "write" their "story" on something as soon as  he was able to do it 😉

Best Regards.