Bit of a weird question, but I work with fire trucks often, and the rollup doors I have use emptys to control the height/width on the model, but is there a way that I use only one empty for both the height and width? Basically I need to constrain some of the verts to the Z axis, and some to the X axis, then some to both.

Sorry for not adding any images when I first made the post, I wasn't able to get any at the time.

I've attached an image below of what I'm trying to accomplish. I need all of the verts in the blue circle to move up, the ones in the red circle to move left and the ones in the orange circle to move in both directions while using one empty instead of two. enter image description here

  • $\begingroup$ My first thought would be to create two shape keys. One for width and one for height. Then assign drivers to control them based on the X and Z positions of the control empty. That would mean your question would be answered by explaining how to create those drivers? $\endgroup$
    – Ron Jensen
    Commented Oct 8, 2021 at 14:27

1 Answer 1


If I've understood you correctly...

enter image description here

  • Hook the vertices under E1,E2,E3 to their respective Empties
  • Give E1 a Copy Location constraint, copying E0 in X only
  • Give E2 a Copy Location constraint, copying E0 in Z only

Hide, and/or lock down E1 and E2, if you like..

Not sure about your other requirements, but you could, say, put another 'Root' Empty at the bottom right corner. Then, if the copy-constraints are all in Local > Local space, you can parent all other components to the root, and move / rotate the rig as you wish.

enter image description here


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