Using curved Line and spline in one sketch for Loft function

[info]

Hello,

I have been using Fusion 360 for about a week now and I am very enthusiastic about its capabilities.

But when I try to make a Patch using 2 splines and 1 rail spline ,it only works when the splines are connected.

When I create a spline in my top view the spline should have 'straight' lines on the side and a curved line on top. Using two separate lines (Line and Curve) does not make the Loft work. So I am forced to draw 1 spline with the spline tool and trying to make the sides as straight as possible. Connecting splines is also not possible, so what's the solution for making 'straight' side lines together with a spline curve on top.

Hope to hear from you all.

Leslie

[TheCADWhisperer]

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@info wrote:

... Using two separate lines (Line and Curve) does not make the Loft work. So I am forced to draw 1 spline....

Leslie 

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I would use the most primitive (simplest)  geometry type available.

If the geometry should be a line or arc - I would use a line or arc.

From the simple geometry - it is possible.

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

[michallach81]

Hi,

 If that two pieces curve (line & spline) serves as rail it should be at least tangency between them. If it's not a rail but a profile then it must be something else that you didn't mention. Please attach file for further investigation.

[info]

I hereby send you my testfile.

In this setup, you will find 1 Loft body made with 1 Spline (which sides are not 100% straight) and 1 curve made out of 4 separate lines, but that is not working with the loft option.

Do you always need to make 1 curve made of 1 spline for using the loft tool in combination with symmetry?

[michallach81 · Accepted solution]

You just need to take care to put right coincident constraints, just look:

[TheCADWhisperer]

Your Sketch1 is missing a Tangent between spline and line.

Your Sketch1 is missing logical dimensions.

I would create one spline (or better yet, arcs if possible) in Sketch1.

I made a few changes.

See attached.

Oops, I found a couple of issues with my example.

I have to get out the door in a few minutes - I will try to post a better example tonight.

[michallach81]

The loft was failing only because there was no coincident constraint between different sketches. Other problems would make that model ugly but doable.

[TheCADWhisperer]

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@michallach81 wrote:

....Other problems would make that model ugly but doable.

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See file that I attached above.

Oops, on closer examination - still not happy with my example when I check with curvature analysis.

I prefer not creating "ugly" geometry.   Embarrassed by my example.

Can you attach the example that you created in your Screencast?

[michallach81]

File attached. It still bad looking, but I was addressing only the core problem of loft failing. We can provide better modeling but that interferes with Leslie design intent, which we know nothing about.

[info]

Thank you Michal for your solution!!

As a already mentioned, I am a new to Fusion and I didn't know about using the coincident constraint and using the chain slection!

This design was not my original model and I made it very quickly to explain my problem.

[info]

Thks for your respond!

I need to start using the Tangent.

[TheCADWhisperer]

As you progress on your design - attach it here for tips.

[info]

Thank you, but unfortunately the designs are confidential.