Hi, Im very new to Rhino and I am trying to design a part for 3D printing and I think I made it wrong because now it has 6 non-manifold edges. I tried the nonmanifoldmerge but it didn’t work and i can’t see the the second thing i would need to select for that tool. Deleting the edge also didn’t work and the whole shape is still an open poly surface and i haven’t been able to close it, could someone please explain how i can fix this? Thanks in advance
Untitledshape1.3dm (2.9 MB)
1 Like
the reason for these to be open is because there is no reason for them to be closed. if you imagine this part being made from your filament, how would you imagine these 2 walls would stay adhered? during printing some connection might occur but nothing really structural, they are connected by one line which is not a solid connection by any means.
if for any reason you want it to be like that and you want it connected you can explode the entire object and then use NonmanifoldMerge.
or remodel these parts: open/delete these faces
loft
do this on all corners then use cap, that will close it up
a more difficult approach but depending on how you want it to look like:
use ConnectSrf on the outer surfaces then delete these surfaces
and loft the edges go close it up
do this on all edges
now you can use CreateSolid to close it all up. that will take care that the intersections below are done automatically, join will not work obviously.
but, that would change the height slightly making also a pointy corner, if you want to avoid that you can build a quick block and use BooleanDifference
hello,
thank for the help, I tried the first method and just using the nonmanifoldmerge after exploding the shape didn’t change anything the same edges were still showing up as non manifold. I also didn’t manage to do it using the second way, caping the holes created 12 naked edges and 6 non manifold ones so it didn’t solve the problem, I was also a bit confused about how i was supposed to attach everything back together after exploding and remodelling the edges, I tried nonmanifoldmerge but that also resulted in naked edges and more non manifold edges. I tried capping it when all of the parts were separate but it said Unable to cap 50 objects. The openings did not have closed, planar loops of edges. For the ConectSurface method which outer edges should i select, I am not familiar with that tool so wasn’t sure which parts to select. thanks for your help
1 Like
Nonmanifold merge is designed to create nonmanifold edges when more than two edges are coincident. All you need to do is join the surfaces after exploding . Join will usually not create nonmanifold edges.
1 Like
well yes that was my bad, i just see that you already had used this one, i thought you are showing naked edges so i mistook your outcome. but like Jim said, this will create nonmanifold edges. which then show up as nonmanifold. nonmanifold means that more than 2 surfaces share one edge, in your case even 4.
if you deleted all the faces from all sides and have joined the object after lofting, then cap closes the object, it did here. since i can not repeat what you did i do you a favour and post the geometry for you.
titled shape.3dm (294.1 KB)
i forgot to mention, cap only works when the geometry is joined, it then closes all planar edges that are surrounded by 4 edges. the result i posted has some extra surfaces laying on the bottom, but it should work for print, you can also get rid of them by exploding the model i posted and use CreateSolid but it really should not be necessary.
Hi,
Thank you for all of your help! I finally managed to do it using the ConnectSrf tool deleting the top faces and then using Loft. This model was only a part of bigger one but I just had a quick question, if a model if made up of multiple objects do they need to be joined together (with BooleanUnion for example or something similar) before exporting the file for printing or would it still work if they are just touching, I couldn’t join/merge because it said that there were no intersections and no open/naked edges.
booelan union works if the geometry clearly intersects, though there are some situations when boolean can fail. it will not work if one of your geometry is open, for boolean to work you have to have closed objects that intersect. that means a plane or any surface that has open edges will produce unwanted results if not fail entirely. faces of closed polysurface that are touching are in fact clearly intersecting, boolean then usually should work.
it also works if there is one edge that coincides with another like here below, though the result will be nonmanifold.
this case as seen below as mentioned will work since faces coincide, then the geometry will be valid closed and manifold.
You don’t need to join. Overlapping volumes a recognized by most slicers as if they are booled.
I often don’t bother of booling polysurfaces. This also helps for quicker modifications.
Boolean difference can be done in the slicer with „negative volume“
If you can live with with the surface quality:
„ShrinkWrap“ will turn anything into a waterproof printable mesh.
1 Like