Parent Vertex to Vertex?

Support Modeling
#1

This problem seems a bit weird, but I can’t think of an easier way to solve it at the moment.
So here comes the problem:
I have 2 separate cubes, now I want vertex A of the First Cube to be connected to vertex B of the Second Cube.
Like having a spacer between them, so when I move vertex A, vertex B moves and rotates the same. But also, when i move vertex B, vertex A moves and rotates at the same time too. I tried it with bones, but I can’t seem to figure it out.

I would call it a both-way parenting? So vertex A is parented to vertex B, but vertex B is parented to vertex A.

Any ideas and help is appreciated.

Greetings, Rhynden

#2

Look at “Hooks” and “Actions.”

A “hook” is an Object that, like a fishhook, can influence vertices. An “action” is a rule that maps the change in one parameter of one object to corresponding changes in the other … commonly used in rigging to create “control levers” that cause various things to happen when they are moved.

I believe that you can’t actually use “parenting” here.

#3

Mhm I tried it, but the Hooks modifier seems to work just like a bone and didn’t help me fix the problem, if I “loop” the hooks, it seems to act pretty weird.
The action editor seems to sound nice, but I do not want it to be an animation, I want to use it in my viewport.
To simplify: Cube A shall move when Cube B is moved, Cube B shall move when Cuba A is moved.
The 2 problems are:

  1. I can’t do it because it would be “Loop parenting”. So only 1 cube is connected to the other.
  2. I don’t want the whole Cube to be parented, but only selected vertices.

Any other ideas?

#4

Attempting it with bones may be the simplest way to do it, or so I believe. (I’m new to blender, so can’t say for certain)

If you only plan to move the selected vertexes but not the cubes, then possibly follow this (Though you wont be able to edit/move the cubes after doing this, only those vertexs will move by the bone(s)):

  1. Create a bone where you wish it’s pivot point to be.
  2. Select the first cube, (shift + select) the bone & press (Ctrl + P) then select “With Empty Groups” so that the bone doesn’t control anything vertexs of the cube yet. (Repeat the same thing but now with the second cube.)
  3. Select one of the cubes, go to edit mode & select the vertices you want.
  4. Switch over to “Paint Weights” mode & press V if you do not see the selected vertixes highlighted.
  5. Go to “Object Data” on the far right menu screen (the Upside down triangle near the modifiers tab)
  6. Click the down-arrow for “Vertex groups” & select the bone on the list.
  7. Make sure the strength is set to 1, & then press “assign”
  8. You then repeat steps 3-7 for the other cube
    And now when you move the bone, the vertexs that you selected of both cubes should move along when you move the bone. Though you can’t move the cube’s position like that, otherwise it would mess with the bone’s calculation.

In theory, if you could use two separate bones. Have boneA control purely those vertexs you want on both boxes, while boneB will be controlling all of the remaining vertexs on the cubes. Then you would constrained boneA’s movements to boneB’s movements. This way if you move boneB, both boxes will move completely including the specially selected vertexs since boneA will tag along, but if you only move boneA, then only the specially selected vertexs of both boxes will move. Sadly I’m barely learning how to use bones, so I can’t help much.

#5

Deadly Pounce has given you a reasonable way to do this, but you really need to understand why your above description creates an endless iteration of attempts to calculate object position that can’t ever be resolved, or else your animation experience is liable to be painful and frustrating.

If you’re not doing a character or a machine, I would just use hooks; it sounds as if you are using ‘hook to new object’ instead of having the hook empty from the first object selected when you enter edit mode on the second object and then choose ‘hook to selected object’.The drawback of the hook is that unfortunately you can’t change or add to the vertices that you hooked, (unless there is some place that i’m not aware of where you can - maybe in the outliner datablocks?)

The hook is a modifier, and you can change the radius and strength in the modifier tab for each object to prevent excessive deformation.

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