How to Close a Open Polysurface!

Cannot close this polysurface. There is a naked edge at the very fore part of the hull. Can anybody help me?

Untitled.3dm (151.1 KB)

Hello -

  1. ExtractSrf the top, deck, surfaces.
  2. Turn on control points for the deck surfaces.
  3. Window around the ones near the very tip.
  4. SetPt snapping to the end point of the top edge if the hull - zoom in to make sure you get the very top, there are some short vertical edges that might grab the End Osnap
  5. ExtractSrf the short vertical surfaces and MergeAllEdges.
  6. Join.

Any luck?


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That’s because that is a lousy way to make the deck surface. Even if you get it to work you still have a degenerate surface that may cause additional problems.

Its much less likely to cause problems if you make the deck as a trimmed extrusion
deck.3dm (137.0 KB)

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Well you can select the top part by using Shift + Ctrl and selecting it, then delete it,
now from Surface menu choose Edge Curves and select the 4 top edges and Enter, that should close it

I’m editing the post because of one missing step:
After deleting the top part and before using the Edge Curves command, we need to explode the whole
Body then Join it again. This step will fix small errors in the body. After this, the Edge Curves will leave no
naked edges.
Untitled_fixed.3dm (307.9 KB)

Hello Pascal,

Could you please help me? I am a beginner at Rhino and I cannot fix the problem although I applied your steps. Here is my window sample. As you can see, there are some weird areas close to the corners.

or here is the rendered mode:

And I also attached the 3dm. file.

Thank you in advance. I’ll be looking forward to hearing from you soon. :pray:t4:

Pinar Aksu

window_sample.3dm (321.7 KB)

Your model is more than 5476 KM away from the origin ! ? Any reason for this?
If you move the object close to the origin the artifact will disapear. Anyway the reason for the artifact is something to do with floating point precision…

I don’t understand. I didn’t do it intentionally, but I think now it is on the origin. Is it? However it still has that weird part… Do you know how can I fix it? :pensive:

window_sample2.3dm (333.9 KB)

Hello - select the object, start Move and snap to some location on the object as the From point. Then as the point to move To, type in ‘W0,0,0’ and Enter. Then Zoom Extents.

Then RefreshShade to finish.

Any luck?


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Oh, thank you so much! :pray:t4: :heart: It worked perfectly.

Best wishes,


Hi Pinar - OK, good - more info here:


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