I have a parent / child relation between two objects. I want to rotate the parent object and get numerical values for translation of a certain vertex of the child object. Is that possible?

Example: Cube is parent of the Sphere. I want to rotate the sphere and get the numerical distance (in mm) that the selected vertex of the cube (right, lower corner) has moved. I want to get the numerical values.
cube parented to sphere with corner vertex selected

  • $\begingroup$ What do you mean by "see the translation and rotation of the child object"? $\endgroup$
    – Tak
    Nov 3 '16 at 12:42
  • 1
    $\begingroup$ It could work in a number of ways, depending what you are looking for, eg: "copy" contraints, pivoting on individual origins, etc. you should better describe (perhaps add a screenshot) qhat you have, and what you want. $\endgroup$
    – m.ardito
    Nov 3 '16 at 12:47
  • $\begingroup$ Would you accept a scripting approach? Could be that it represents the most practical choice, as it'd introduce you to the scripting functions. $\endgroup$
    – roamcel
    Oct 27 '17 at 5:36

You can get this information with a vertex parent, and a driver.

Start by adding two empties at the corner of your cube, the point you want to measure, (I named my empties "corner" and "original location").
Vertex parent one of the empties to the corner vertex of the cube. (Select the empty, select cube Tab into edit mode, select the vertex then press CtrlP) cube and two empties at corner

Now you know the original location of that vertex and the vertex parented empty will tell you the new location.

Add another object, any object (does not matter at all). Put a single driver on one of its transform channels.
driver settings

Now open up the Graph Editor switch to the Drivers mode and click on the transform channel on the left. When you open up the proprieties region N, you will see something similar to the image above.

You first want you make sure the variable name is in the expression field. Now set the variable to Distance, and put in the two empties you added earlier as the objects in that variable.
The output of that driver is the distance the corner of your cube has moved. If you have your scene units set to Meters, then it will be in millimeters.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.