Hi mat, well there is a MergeSrf command in Rhino but it can only merge untrimmed surfaces where they touch at edges. Your surfaces are trimmed out pieces of a larger underlying surface. It looks like the underlying surfaces could be merged though so you could try doing an untrim then MergeSrf then retrim.

- Michael

Hi Michael,

Untrimed the surfaces in Rhino. Selecting Merge...Rhino says select the two surfaces to merge...but it only allows me to select the big main surface. Any idea?

File attached.

Thx

Hi mat, in that file there are 2 objects, the big one is a single surface and the fillet like one is a polysurface made up of 2 surfaces joined together.

The Rhino MergeSrf command only works on single surfaces, it won't allow you to select an object made up of multiple surfaces. You would need to use the Explode command on the multiple surface object to break it into individual surfaces before you'll be able to select it for merging.

But also you may need to cut that fillet surface in half because MergeSrf may not handle making a closed surface like that would form. You can use Split with the Isocurve and Shrink=yes options to cut the longer piece so it won't be trying to merge into a closed result.

- Michael

Thanks Michael. I'll give that a try.