loft technque help

[laughingcreek]

I'm trying to get a better handle on lofting techniques, namely defining curves in a way that the loft tool will except.  Currently I am looking for an efficient way to break spline curves into the segments that loft requires.

The attached file has a very simple set of curves for producing a loft with a fading crease.  (the bottom left cornet is funky, but lets not focus on that right now ;). 

Right now the only way I can figure out how to loft these lines is to-

-3d include them into a sketch (Sketch 13)

-delete the 3d include constraints

-break each line at the intersection

But once that's done, sketch 13 is no longer parametric, so it has to be completely redone when little changes to the originating splines are adjusted.

Any suggestions on a work flow would be appreciated.

here's a pic of the lines with numbers to help in discussions.

[jeff_strater]

Hi @laughingcreek,

I have not had a chance, yet, to look at your model, I will do that shortly.  However, there are a couple of techniques that I use when setting up loft profiles and rail curves. See:  introduction-to-loft-using-rail-curves-in-fusion.

Let me see what I can find in your model.

Jeff

[laughingcreek]

Thanks Jeff!  Good info.  You'll note when you see the model that I actually use some of the methods you outline.

The problem isn't creating the loft it self, that works.  The problem is creating the guide curves in a way that they remain parametric.

The only way I could see to create the loft with the fading crease was to split the curves into shorter segments.

Another way would be to create the splines in multiple segments, and tie their spline handles together.   But that gets real messy real fast, and then I get into chicken and egg type problem any way.  I wouldn't know where to break line 1 until I create line 7 for instance, (with out going to DM mode.  but then I'm not parametric again)

here is a screen shot of the surface-

[jeff_strater]

Is there a reason this needs to be done with 3 lofts?  If you are willing to do it in two, this approach can work, without sketch13 at all:

Jeff

[laughingcreek]

Your screen cast isn't coming through yet, I'll look when it does.  In the mean time I was able to do it with just 1 loft, working left to right with the profiles, top to bottom with the rails.  The crease isn't as nice. (fades out faster)

I am actually trying to recreate a problem I have with a more involved model where it would be REALLY nice to be able to define loft segments "point to point" as it where.  This turned out not to be a good example for that problem.  Will try again.