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tetrahedron nested in a dodecahedron tetrahedron nested in a hexahedron cube

Is there a way to easily snap vertices known to lie on the surface of a sphere ? In these cases the Z axis vertices are aligned at spawn, and no snapping occurs at the selected vertex, while rotating.

Why isn't Blender recognizing the matching coordinates ?

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  • $\begingroup$ you're playing with the golden ratio? $\endgroup$
    – user62213
    Sep 20 '18 at 22:26
  • $\begingroup$ as much as I can $\endgroup$
    – t8ja
    Sep 20 '18 at 22:42
  • $\begingroup$ Well, I've done everything in writing, I've never tried it here starting because I would have to correct the value of pi in the code and the only attempt I made to test how the satellites that orbit the earth crash, my calculation of physics takes too long , but exactly what do you mean by lack of snapping? $\endgroup$
    – user62213
    Sep 20 '18 at 22:48
  • $\begingroup$ you could put your blend file to analyze the problem $\endgroup$
    – user62213
    Sep 20 '18 at 22:50
  • $\begingroup$ Do you have any educational purpose or is it just for sport? because I can think of a very mediocre solution if it is only to demonstrate a graphic, but if it is for educational purposes it requires more meticulous work $\endgroup$
    – user62213
    Sep 20 '18 at 23:35
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With snap always set to 'Vertex' and 'Active', Pivot at '3D Cursor'. All transforms in Edit Mode, with all vertices selected, and a convenient vertex active. Usually you will translate-snap the active vertex into place, put the 3D Cursor there, and then with another vertex roughly opposite the cursor made active, uniformly-scale or rotate all the vertices about the 3D cursor.

All objects created from Extra Objects > Math Function > Regular Solids

enter image description here

  • Dodecahedron to Icosahedron: AltP Poke all faces of the Icosahedron, scale all vertices of the dodecahedron, snapping the active vertex to one of the new face centers
  • Cube to Dodecahedron: scale the cube and snap the active vertex to one of the corners of the dodecahedron
  • Tetrahedron to Cube: the solid can be snapped, by progressively moving the pivot point and setting Custom Orientations, but easier to snap individual vertices of the tetrahedron to the appropriate corners of the cube.
  • Octahedron to Cube: poke the faces of the cube, and scale, as we did with the dodecahedron.

What Blender's snap system is missing (compared to some other 3D applications,) is the ability to set a snap orientation. You can constrain the transformation of the snap source, but not the vector from snap source to snap target.

But, given that, sure you can snap during rotations, scales, and translations, constrained ones, if you like.

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  • $\begingroup$ I'm not following. Make a GIF doing exactly what I was trying in one of my screenshots. There's no way I know of (in edit mode, vertex select) that makes the static vertex (I want to snap to) active, while the mesh that has to be totally selected in order to rotate as a whole, matches the other meshes vertices in multiple locations (which is incidental considering only the active one is considered). $\endgroup$
    – t8ja
    Sep 21 '18 at 15:35
  • $\begingroup$ The 'active' refers to the source, not the target. So I can select a bunch of vertices, with one active. Then move/rotate/scale them all in the same way, snapping the active vertex to my chosen static target, with the rest following along. $\endgroup$ Sep 21 '18 at 15:41
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Thanks to Robin Betts I figured it out.

With SNAP set to 'Vertex', 'Active', Pivot at '3D Cursor'

Edit: selecting the static mesh, actually isn't necessary

  1. select the static mesh, then select the "to be" transforming mesh while holding "Shift"
  2. enter "Edit mode", "Ctrl+Tab" (Vertex select mode)
  3. Press "A" to select the whole transforming mesh
  4. Hold "Shift" and de-select one of the vertices (the one you want to snap), then re-select it, still holdig "Shift" (which makes it active, more orange)
  5. Make sure 3D Cursor is at the desired pivot point
  6. Make sure your pointer arrow is near the "to be" moving vertex when you press "R" then "Z" to constrain the rotation to Z axis
  7. Bring your active vertex close to the static one, and it will SNAP solution
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  • $\begingroup$ If Robin Betts answer helped you, you should upvote it $\endgroup$ Sep 21 '18 at 16:21
  • $\begingroup$ I did, but a notification comes up saying my low reputation prevents my votes from being publicly visible. $\endgroup$
    – t8ja
    Sep 21 '18 at 16:27

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