Control the BlendSurface

Hello all,

I am working on a little fish and on one side I want to have some extruded squares as a decoration.
So I projected my curves onto the surface and made a small extrusion.

Now I want to close the top and the best way to me, seems to be BlendSurface. On the other side of the Fish it works quite well, but there I have rather small circles.

In the case off the large squares, i’m running into the problem that on sides where the curvature of the fish is extreme, the newly created surface is creeping into the surface edge.

What I want is a gentle rounding along the edge of the square. I know that I could split the FishSurface with the projected curve and use the cutout square to work with, but I like very much the non-planar quality (relative to the rest of the fish) of when I use BlendSurface.

Any advice you could give me?
Many thanks, Robert Glotzbach

Fish_02_01 014_SquareTest.3dm (232.0 KB)

Hi Robert - does the attached look anything like what you want?
Fish_02_01 014_SquareTest_PG.3dm (227.7 KB)


Thanks a lot Pascal,

Yes certainly it does, i would like however, to be able to control the bulging out of the surface if possible.
And eventually i need a nice fillet to the main surface like in the attached picture.

So whats your secret here :slight_smile:

Many thanks for helping.

Kind regards, Robert

PS It seems that you have created a surface and then trimmed it, how did you create that surface?

Hi Robert - see the attached - the surface is created with Patch, with History. The inputs to the patch are the edges of the existing surface and the four red points. I did not ask for tangency adjustment, and I used 30 by 30 spans. By (carefully, Gumball is handy) moving the red points, you can adjust the bulge. When it looks right, a FilletSrf at .08 cleans up the edges.

Fish_02_01 014_SquareTest_PG_2.3dm (279.8 KB)


Thanks a lot dear Pascal, this is perfect :slight_smile:

Kind regards, Robert