MergeSrf error

Hi, I found something strange:

In the attached file there are a few original surfaces. These surfaces represent only the right side (Starboard) of this model.
When I mirror these surfaces and use MergeSrf to combine the two sides followed by an OffsetSrf the parts do not line up with the original surfaces. I calculated a diviation of 5mm.

Any ideas?

Merge error.3dm (7.6 MB)

Hi Thomas,

MergSrf will change the shape of the surface when the option Smooth=Yes.
This surface has a degree of 5 so it will affect the shape all the way to the end.

Exaggerated below

An option is to set Smooth=No, however that will cause the surface to have a ‘crease’, that might give problems when offsetting:

In your example however, the merging with Smooth=No does not seem to cause much trouble when offsetting, only when editing the points you see the crease is present:

HTH
Groeten :smile:
-Willem

Haha Thanks Willem!!

The Smooth and Roundness setting did caused to problem!