Does anyone else spend hours trying to get a closed polysurface?

It is maddening that there is so little information, plugins or something to get around constantly trying to adjust edges and points to make a watertight model. I honestly don’t understand how you do it?
I’ve built different things in Rhino over the years and this is my main gripe with the software. I really can’t justify the time spent on this single issue to keep using Rhino.

Am I missing something?

I do a lot of exploding, adjusting, joining, remove naked edges command etc.

I make sure everything is planar, use setpts, have adjusted absolute tolerance. Why in the world is there not a command to just force a damn polysurface together. Again, maddening. Arguably unusable. Literally trying to join a straight corner together seems impossible.

Hello- probably best to post an example file.


naked edges example.3dm (186.5 KB)

Funnily enough I exported the model over to blender as an obj and it took minutes just to get a watertight model for the purposes of 3d printing. Which I can, I suppose, import back and do a meshToNurbs conversion, if I need to tinker with it further.

dear @boaskristjansson

my guess - try to explore some different / new Workflows.
make sure you use proper objectsnaps (less is more, only end / midpoint)

here is a fast rebuild from scratch

use world top for position / easy symmetry

_box (3 times)
_polyLine on top face
_polyLine (right view) proper object snaps, project = yes

_setPt to make sure i did not catch any errors from the input part

_extrudeCrv (the red curve)

_wireCut (with the blue curve)

inbetween the steps i check, if i still have a closed PolySurface…

looks like your original part is not 100% symmetric ?

naked edges example_tp01.3dm (3.3 MB)


hope this helps - kind regards

(edit: screenshot)

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@boaskristjansson it could be that during modeling you are inadvertently moving stuff. Two things can help to avoid this: using gridsnap (so that you notice moves better) or adjusting a setting in Rhino that prevents you from moving while selecting. This is not my personal preference, but some people swear by it.

@Tom_P already gave some pointers on how to build this properly, but in case you wanted to repair this model in Rhino, I found a couple things in your model, that I best show in this video:

A big problem with this object seems to be overlapping surfaces.

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if your goal is simply 3d printing, then shrinkwrap is your new best friend.

see this video-

if you want to learn to repair your files, see this video-

Hello- I think you are working too hard… what you have in your example model should be very straightforward - if you see corners like this

something is amiss. What is your building process ? Something like what Tom describes is a good one.


Thanks! Will check these out for sure

Thanks for the suggestions and detailed step by step. I was working with point and vertex snaps.
Symmetry was definitely off with all the messing about.
I’m unfamiliar with the _wireCut command. Thanks for that.

You are probably correct I should have switched workflows and used the open, non symmetric poly as a reference and started from scratch with a new shape.
I haven’t modeled with Rhino for a while so my logic was definitely off.

Appreciate the input!

Thanks will definitely check the Drag setting. After watching the video example I must admit I have no idea how you managed that. I’m familar with cap but ofc that requires planar curves I assume. Not having some kind of screencast keys makes it hard to follow. After you delete the two top surfaces you are able to select the entire loop, how did you do that? And somehow after joining everything is aligned and you can just cap, done??

Definitely been working on this in a dumb way. I should have rebuilt everything from solid shapes after it got so misaligned.

not sure what you mean by “open”.

check the file i posted - it shows the steps, layer by layer.
I use one open curve for the wirecut (other workflows are possilbe)
the other curve is closed
the solids / polysurfaces are always closed in all steps.

there is one small (self) critic in my workflow:
the boolean union of the extrusion with the rest, has some coplanar faces.
be careful with stuff like this - this is why my workflow will not make it to the school-book.

I know youre in love with shrinkwarp… but isn’t this a
a sledgehammer to crack a nut
( in german(y) we are shooting sparrows with cannons )

Apparently, after deleting the misaligned surfaces (3(!) top and 1 bottom surface), selecting everything, and _Join, then _Cap could make this into a solid. However, this is just to indicate a couple issues in that model. Better is to improve accuracy in your drawing from the start.

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Danke schön! I hadn’t checked the layers. Makes sense now

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