Need help advancing from curves to extrusion


I’m working on a model of a cabin. On each side you can see the contours of two rooms and in the middle a tunnel looking like a double vortex. I’d like to make the tunnel solid and place it in the middle of a box. Then use the boolean tool to shape the tunnel into the box, being defined as walls.

How do I do that? :smile:

Hi Norman - I am not visualizing what you want to do very clearly I’m afraid, but I guess it involves making a volume from the white curves in the middle of your image, right? Can you post your file?


Does this fiiine illustration give you any clue? (-:

Hi Norman - OK, got that, but the challenge here is making the inner volume to the shape of the white curves - right? Once we’ve got that, trimming it into a box should be straight forward. It looks like you have enough curve info there to make a NetworkSrf, if you pick the right curves and Join them to make a valid network for the command. There may well be other options but it’s hard to say without the curves.


Yes, that’s exactly my issue. I got an inner and an outer circle. These are connected by curved lines at four different points on each circle. The curves comes in different shapes, so the main task would be to get the program to define average curves based on the curves on each side of the quadrant. A little Rhino math would do the trick.

Hi Norman- see how the attached file seems to you- to close the object, use Cap, if needed, The curves are trued up a little where you see the lines to make the segments truly tangent before joining. The network is then the long open curves (joined into just the four curves) and the rings (joined) going around the shape.

Klimakammer5_PG.3dm (312.8 KB)


Cool! Thank you, pascal. That was really neat of you. Could you tell me what you did there? Which commands?

Hi Norman - to clean up the four open curves, I lined up the control points according to the line segments that you see there - note the NetworkSrf would have worked without this adjustment, but this is cleaner- in general, always always always make sure that curves that are meant to be tangent are in fact tangent.

See the bits about curve continuity in the pdf file here -

It’s RhinoForWindows-centric but the info is exactly relevant to this.

Once the curves are clean, tangent, and Joined, then NetworkSrf is the command I used to make the surface.


Hello again! I have a follow-up question.

I’m now about to make a “cave” out of this volume. But to make it a more functional place to sleep, three of the curved corners of the vortex needs to end up in each of the three corners of the existing volume - as showed on the attached picture. How do I reshape the curves of the open polysurface?

Editing the existing surface to meet the sharp corners would require some trimming back of the organic surface first and the deletion of the planar surface currently meeting at these corners. Then use DupEdge to get a curve from the sharp corner border and use loft with the loose option between it and the trimmed edge of your organic surface. Or make several profiles and use loft to form a new surface ending at these corners. It would look something like this if you use multiple section curves in the loft…