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enter image description hereI made a specific model of an empty Torus with some cylinders sticking out. I am planning on 3d printing this but all kinds of problems arose with the joint between these 2 objects. I am planning on "solidifying" the model in the 3d printing software, but for the moment, can someone help with fixing the geometry of the model linked so that it can be 3d printed. Thank you! :)

enter image description here

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    $\begingroup$ Hi, and welcome! The site provides tools for including images in your post: here, it helps prospective responders to decide whether they want to download your file. $\endgroup$ Jun 5 at 19:05
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    $\begingroup$ Have you tried using the solidify modifier in Blender rather than using the solidify functions in your 3d printer software? $\endgroup$
    – Eric Xue
    Jun 5 at 19:55
  • $\begingroup$ @Eric Xue yes I have. It creates errors in the seams of the cylinders connected to the taurus which means that this is where the error in the mesh probably is. I cant seem to fix it tho thats why im asking for help. $\endgroup$
    – samervjr
    Jun 5 at 20:57
  • $\begingroup$ A) Which way is it solidifying? B) how were those cylinders connected? C) try selecting all and merging vertices by distance, or dissolve degenerate, and then maybe triangulating the mesh. $\endgroup$
    – TheLabCat
    Jun 6 at 2:39
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    $\begingroup$ @ZargulTheWizard A) solidifying inwards makes the error in the inside of the joint and outwards on the outside. Both give apporx. the same error B) boolean modifier with union C) I'll try and see if it works so thanks for the tip! Removed 42 vertices which is insane considering they were hiding there all along :) $\endgroup$
    – samervjr
    Jun 6 at 12:25
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A subdiv. modelling approach would aim for clean topology from the outset. It may be a bit more trouble.. I guess it's a weigh-up, considering the final resolution of your printed surface.

For this method, retain an intact, subdivided copy of the torus. You can hide it; it's going to be a shrinkwrap target.

Here, I've worked on 1/4 of the torus, with the extruded pipes directly opposite one another, for convenience. The inward-facing part of the torus can be cut, rotated by 45 degrees, and welded back later.

  • You would match the number of vertices in the holes in the torus to the corresponding circular pipes..

enter image description here

  • (left) the outside circles had 16 vertices on a default 32-torus, the inside circles, 8.
  • There are various ways of projecting the circle onto the surface of the torus.. here, just using Snap, set to 'Face' and 'Project Individual Elements', looking straight down Y in an orthogonal view, and hitting G.
  • Then (middle) you can delete the hole in the torus,
  • ..and fill the gap, with Bridge Edge Loops, or by repeated F filling.

Then you can extrude your pipe-cylinders.

Now a common way to get a very smooth transition is to set up a vertex-group on the main body of the torus, excluding the extrusions. Then give the torus a Shrinkwrap modifier (target, your reserved torus), affecting only the vertex-group, so it doesn't collapse the pipes.

Then you are relatively free to make adjustments to the vertices around the join, on the torus. For me, relaxing and smoothing the vertices around the hole helped to get rid of artefacts caused by the 5-edge poles at the corners.

After Catmull-Clark subdivision, the topology looks like this:

enter image description here

..and the whole thing can be given Solidify, Bevel (by angle), and Subdivision Surface modifiers. ( I had to cut the ends off the pipes.. I kept them capped, while working )

enter image description here

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Specifically for this kind of object modifiers served quite well too.
It is non-destructive way ... but yes, setup is very fragile :) So it is still recommended to use Robin's proper way, but can be useful as WIP.


Based on default Torus and several Cylinders (8sided).

Usually Subdivision modifier fails on boolean operations, but since topo quite matched, I was able to use also Bevel connections and ends of tubes thanks to Weld modifier, that merged micro inaccuracy of Booleans.

Edit

Eventually you can apply modifiers without subdivision and add one more loop cut and cut n-gons to quads ... to get beauty, because the first image is not smoothed enough on beveled edge on very close look :)

enter image description here

Or probably you don't need to bevel connections at all ... so you don't have to care.

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  • $\begingroup$ I reckon this is probably fine for printing.. and much quicker.. :) $\endgroup$ Jun 6 at 21:59
  • $\begingroup$ @RobinBetts ... probably not quicker ... setup takes a time, but I like to easily change things on a fly :) $\endgroup$
    – vklidu
    Jun 7 at 8:38
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if you select these faces here:

enter image description here

and then triangulate them:

enter image description here

and maybe optimize some faces manually...

enter image description here

solidify looks like this:

enter image description here

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