topic Re: Loft with rails giving errors in Inventor Forum

Loft with rails giving errors

mschena1148 — Mon, 25 Jul 2022 01:34:34 GMT

I have a loft that I am trying to create between two dissimilar shapes and 3D rails. Whenever I try this, I get an error telling me that my rails are not smooth, but they are. I have included the example. My rails are two 3D sketches shown by the yellow lines. What am I doing wrong?

Re: Loft with rails giving errors

blandb — Mon, 25 Jul 2022 22:13:59 GMT

I recreated the vertical arcs that are used to make the intersection curves, and it works fine... Not sure what was wrong initially.

Re: Loft with rails giving errors

johnsonshiue — Wed, 27 Jul 2022 21:13:29 GMT

Hi! I took a quick look at the part. The rail in 3D Sketch5 is too drastic. It has a short portion parallel to the profile progressive direction. It is not a desirable rail.

The curves in Sketch10 lack a tangent constraint. Please add it. Then 3D Sketch6 can be used as a rail to Loft.

Many thanks!

Re: Loft with rails giving errors

mschena1148 — Wed, 27 Jul 2022 02:03:15 GMT

Can you show the output? What did you do to redraw?

This is the error that I get. The curves are smooth and interset with the two sketches that I am trying to loft

Create loft feature failed
Loft Example.ipt: Errors occurred during update
Loft1: Could not build this Loft
The attempted Loft operation had problems with the specified rail curve not being smooth. Try with a different rail or try to make the curves of the rail smooth across interior vertices.

Re: Loft with rails giving errors

mschena1148 — Wed, 27 Jul 2022 02:06:24 GMT

Hi Johnson,

Can you show me a screen shot of the output. I cannot get it to loft at all. I'm not sure what you are constraining for tangency.

I get the error

Re: Loft with rails giving errors

JDMather — Wed, 27 Jul 2022 12:14:45 GMT

@mschena1148 wrote:

Hi Johnson,

Can you show me a screen shot of the output. I cannot get it to loft at all. I'm not sure what you are constraining for tangency.

Sketch10 was missing Tangent constraint between these two curves.

There are other issues as well.

If I build one surface at a time I observe that there is a self-intersecting issue.

Additional rail or section profile is needed.

Re: Loft with rails giving errors

blandb — Wed, 27 Jul 2022 13:19:53 GMT

I must have made the rails a little different and unintentionally removed the intersecting curves as @JDMather had pointed out and that is why mine worked...I assume.

Re: Loft with rails giving errors

mschena1148 — Thu, 28 Jul 2022 01:05:57 GMT

Thank you for your help. It was the tangent constraint for sure!