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Description

I am trying to use blender to visualize a molecular systems. One of the issues I am running into is creating a box that shows the domain of the molecules. In order to do this I need to combine three non-orthogonal cylinders with a sphere in 8 places to form the box. I would prefer a solution that ends up with one fully connected mesh that is rounded (not necessarily perfectly spherical) and could be implemented using blender scripting.

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What I have attempted

  1. Adding a uv sphere to the end of the same radius

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  1. Adding a uv sphere of slightly larger radius leads to jagged edges at sphere cylinder interface. If worst come to worst this is the solution I will use.

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  • $\begingroup$ Can that help blender.stackexchange.com/questions/77889/…. Imagine a cube from which 3 faces are extruded. i.stack.imgur.com/FjG9V.jpg $\endgroup$ – lemon Apr 27 '17 at 14:12
  • $\begingroup$ I looked at that technique and my critique is that it does not look easy to automate with scripting and looks very hard to do precisely. $\endgroup$ – costrouc Apr 27 '17 at 14:43
  • $\begingroup$ I think you should provide more input about the constraints, the needed precision, data you are starting from and so on $\endgroup$ – lemon Apr 27 '17 at 14:44
  • $\begingroup$ The most straightforward way is Boolean Union either with modifier (in Object mode, objects must be separate ones) or in Edit mode from Ctrl+F menu (all objects joined including sphere). However you'll need to convert Ngons from there. You can also use Pipe Joint addon which was included into Extra Objects addon. $\endgroup$ – Mr Zak Apr 27 '17 at 14:59
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It might be an idea to use the skin modifier in combination with particles? It's pretty easy to set up and manipulate.

  • Create a mesh and then in Edit Mode delete 'Only Faces' - essentially leaving you with a wire-frame.
  • Add the skin modifier and then a sub-surf modifier to smooth.
  • Create a Sphere object.
  • Add a particle system set to hair and choose Verts from Advanced settings.
  • Under Display choose the Sphere object.

The particle system will have to be moved up to the top of the modifier stack.

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  • $\begingroup$ Wow what an elegant solution and perfect for scripting. Thank you for introducing me to the skin modifier. Additionally I found that you can adjust the radius of the "skin" by adjusting the individual vertex radii. $\endgroup$ – costrouc Apr 27 '17 at 20:22
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  • Mesh Loop Tools is a Free included Addon. Very easy to use in this case. Install and be prepared to use in Mesh Edit Mode.
  • Numbers on bottom indicate columns
  • Simple Cube. Bottom Row 1.
  • Be in Edit Mode for most of what follows.
  • Loop Cut 3 different Times on X,Y, Z planes. Choose 17 Cuts, Suit to taste. Result is high density mesh. All Quads.
  • Menu Transform To Sphere. Highlighted Shift Alt S. Sphere with geometry six sides. All quads. No Triangles.
  • Delete Vertices to taste on 1 to 6 sides of sphere. Bottom Column 4. Yellow Sphere with blue filler for legibility.
  • Select a single square cut out edge from step above. Loop Tools Circle W Loop Tools Circle. Square edge is now circular..
  • Top Row Yellow. Select Circular Edge. Extrude X.
  • Select Next Circular Edge Extrude Y.
  • Consider Loop Tools Bridge. In a single object select two different circular edges. One from joint and one from cylinder. Loop Tools will join them efficiently. You may not need extrude if you Bridge Edge Loops.

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  • In the image above is detail with a Subsurf Modifier. You may choose to customize the circular shape with awareness of what the Subsurf Modifier will do. An extra loop cut was added as indicated by the arrow tip that may suit your taste. Those small fine lines of loop cuts are difficult to see. Click on image to see larger version of image.

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