MergeSrf works and doesn't work?

Hello, somebody can explain to me to what factors it is necessary to pay attention when using “MergeSrf”? In one cases it works, in others is not present what influences it?


Why at present the option doesn’t work? 3 surfaces don’t unite…

Untitled.3dm (350.8 KB)

You can only merge surfaces when the adjoining edges are untrimmed. You are trying to join trimmed edges.

Shrink will shrink a trimmed surface to trimmed edge if the trimmed edge is an isocurve. The edge of the hole in the main body is not an isocurve so you can’t shrink the surface to that edge.

The trimmed edge of the projecting “spout” is an isocurve and Shrink will shrink that surface to the edge. After using Shrink you can merge the spout and the blend surface.

RichardZ, davidcockey, many thanks for information!
At me it has turned out to unite the 1 and 2 surface, but what to do with the 3rd surface?

It is necessary to me that I could edit easily the object by means of control points (and T-Spline) made of 10-15 surfaces…

It is simpler to work with an object nurbs consisting of one uniform surface, than to work with the object consisting of 10 surfaces and that them it is necessary to unite Join, but in that case - polysurface turns out, and easily not on you edits it, also in T-Spline you won’t throw.

My transition is similar to it:

And it is necessary that was approximately so (smoothly, exactly, any triangles, it is easily edited), but for this purpose an object has to be merged in uniform:

How to do without Trim?

If to do in T-splines - the model which is very easy for editing turns out, but as if I didn’t convert into mesh - the grid turns out not really equal (with triangles). When converting in nurbs - an object turns out not uniform (with a set of edges).

Untitled.3dm (278.5 KB)