Blending 2 surfaces

Hi all,
I’m trying to Blend 2 surfaces but I’m not able to do it nicely. I’m attaching the file, so you could please have a look and let me know what is happening. It needs to be blended, but it is not working properly. The edges?? Please let me know how would you do it.

blendSrf_1.3dm (7.0 MB)


I assume you want to blend the small “bumps” with the fuselage.

What command are you trying to use? BlendSrf is usually used to fill a gap between surfaces, not to blend surfaces along a coincident edge. To use BlendSrf you will need to first trim the surfaces to create a gap.

An alternative is to use FilletSrf which will create a fillet (with circular arc sections) between the surfaces, or ChamferSrf which will create a chamfer between the surfaces. You can also use one of these commands, delete the resulting fillet or chamfer, and then use BlendSrf to create a smooth blend surface between the original surfaces.

One edge of the “bumps” is split. Is there a reason for this? Split edges sometimes create problems.

The “bumps” are 2 edge surfaces which results in skewed isocurves. This can cause difficulties. A better approach to modeling the bumps would be to have top and bottom “rails” and use Sweep2 cross-section curves of the desired shape.

Thank you for your post David.
I created the “bumps” with Sweep1, and that’s the reason of the split in the inner section. I´ll try as you are saying…

  1. Create again the bumps with Sweep2
  2. FilletSrf
  3. Trim the FilletSrf created
  4. BlendSrf

I´ll see how it goes.
Many thanks

Keep it simple with sweep 1 then trim and fillet.

I like @Stratosfear’s way - what you have in the original bump surface is acomplex surface that is trying to be the shape of the bump AND the transition to the fuselage at the front at the same time., so you have that s-shape in plan and a rather awkward surface structure

but the shape hits the fuselage hard in the other view:

Better, I think, to keep the shape and transition separate - make a simple intersecting shape that has only one bend, into the fuselage:

Then work on the transition - a fillet might be enough or you can get fancier if needed.