Issue with different surface lofts from mesh section sketches

[ethanA7E82]

Hi, 

I am trying to do a loft in the surface enviroment from a large amount of mesh section sketches, which don't all have the same amount of points on the spline that makes that sketch. Is there a way for the loft tool to "nicely" transistion from having the point on one sketch to not on the next? I am ending up with lots of little ridges, which I think are causing it to fail when I try to thicken the body. 

Ridges in question. 

Part file should be attached to this post. 

[laughingcreek]

you might can tame the loft by adding rails, which will define the point to point locations, but I don't think the general approach of lofting this area is an approach that is going to work well for this part.

[thoreaubakker]

This is beyond my experience / expertise, but one suggestion would be to simplify / reduce the mesh sections.
Maybe a mesh reduction / decimation in Fusion or Mesh Mixer. Or perhaps drawing new lines snapping to the originals, with consistent spacing?

Again just brainstorming here, no my expertise.

[ethanA7E82]

How would you approach it? I had tried modeling it regularly before, but when it got to the strange "wiggles" in the center, I couldn't get it to match. 

[jeff_strater · Accepted solution]

@ethanA7E82 - a few recommendations:

First, you have way too many profiles in this loft.  You can probably get very close to this mesh with 1/8 to even 1/10 of the number of profiles.  That loft has 57 profiles in it.  You can hardly even rotate the view with the time Fusion spends just painting the labels:

second, each profile is made of of separate curves.  This is what really causes the point mapping to get confused. 

If you go back and re-fit those splines (yes, I know that is a lot of work), you can come out with a much better loft result.  Re-fitting those using Fit Curve to Mesh Section is really just two clicks - start and end point with the type set to spline.  I noticed that some of the mesh sections are not complete, and then it's a bit more work to get the spline, but it is still not that many points.  In this example, I took just one section, and replaced about 20 profiles with 4, each with only one spline in it,  This completely gets rid of the wrinkles in the surface:

because each profile has only one curve, so there are no midpoints to map.  And even though I was not very careful, the result matches the mesh pretty well.  You could do much better pretty easily.

so the moral of the story is:  lots fewer profiles, and one curve per profile.

[ethanA7E82]

Thanks Jeff, That made a big difference. I figured that with more profiles I would get better detail, but with about 15 I am getting more than enough. Thanks for looking into it.