loft fail

loft fail test

3 Answers

I think the mistake must due to overlapping profile

It is likely too complex for the loft tool to solve.
You did a good job of matching the number of vertices between the profiles, but:
1. Your sketches are terrible. I can't even imagine how you sketched them without using any constraints. Normally you'd want lines to be tangent to sketches, not to mention defined with dimensions.

2. Guide curves don't "have" to line up with vertices in the profiles, but that is how it is normally done.

When Solid Lofts fail, you can try a Surface Loft. Sometimes those are a little more forgiving.
But, Boundary Body/Surface is usually a better tool, so I just used it.

There is a Solid Boundary tool, but I always forget it exists, and just use the Surface option (I think it came out first?).
Some screenshots are attached showing the process, and the resulting body.

You might be able to do this with a single Boundary Cut feature, give it a try. At least we know it works as a Boundary Surface which is then used as a cutting/trimming tool.

I did my work in SW 2017, so you won't be able to open the file.

When smoothing does not work, I copy the sketch and move the points to be sure not only to have the same number of points but that these sketches contain the same relationships. I took this habit by working with Illustrator and CorelDraw for "Shape Gradients". And it works with Solidworks. As if the programming of functions must recognize certain elements. ??? Complex functions can be simplified by simplifying the geometry. Also each point should have a meeting point relationship with the guide curves rather than just a coincidence.