Loft with rails giving errors

[mschena1148]

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?

[blandb]

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

[johnsonshiue]

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!

[mschena1148]

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.

[mschena1148]

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 

 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.
 

[JDMather · Accepted solution]

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@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.

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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.

[blandb · Accepted solution]

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.

[mschena1148]

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