Loft with a rail from two splines

[mailT9AA4]

given this design http://a360.co/2aLtX2d

I"m trying to loft between sketch38 and sketch 39

using two lines. when I click on one line, it gives me the error that it's got to touch all profiles. fine.

So I click on the other line and it wants to start a new rail.

The rail lines are "smooth" (to use a term from another answer). They are projection from sketch "top outline" to "top nose level".

In top outline, I've added a tangent constraint between the spline and line used to form it.

Another question asked for the ability to join lines. This is a case where such a feature could be useful.

How to get it to work?

Miles

[Beyondforce]

Hi @mailT9AA4,

Could you please attach the file inside this post. I tried to open it and I got an error.

Ben.

[jeff_strater]

The problem with Loft and Rails is that Loft is very picky about the rails actually intersecting the curves of the profiles.  You have to do a Project Intersect to make absolutely certain that they intersect.  So, you need to do this in a certain order.  Usually, that is profiles first, then rails, but there is nothing saying that it has to be that way.

I will prepare a screencast for you showing one way to achieve something similar to this.  Hopefully it will get you on your way again.

Jeff

[jeff_strater]

OK, this is more complex than I thought.  Thank you for sharing your model - that really helps.

The problem is really a bug in Fusion, to be honest.  You couldn't have known of this bug.  But chaining in loft rails has a problem when working with projected geometry.  And your "top nose level" sketch (good idea to name things with meaningful names...) is projected from the "top outline" sketch.  Which totally screws up rails.

The workaround that I used in the screencast below is to just draw a new sketch, all with two splines, of the top view at the correct level.  The key part here is to use Project Intersect to get the precise intersection points into the sketch, and be sure to snap to them when drawing the spline.

The second trick is to turn off chaining in rail selection, and use the "+" to add a new rail for the other side.  Otherwise, Loft will try to put the rails all together.

Hopefully this is clear.

Jeff