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I would like to be able to 'push' multiple Rigid Body objects up along Z-axis (using another Rigid Body). The trick is that they must only move on the Z. And once pushing force is gone the objects should fall back along Z-location - like gravity but without spinning or rolling.

Using the regular Object Constraints seems to be completely overruled by the Physics.

Currently working in Blender 2.82 and/or 2.91.2 and I found a very nice youtube-guide for Blender 2.76 with a Sensei-add-on (https://youtu.be/7jwqXgdBM_g?t=1170) but I cannot find the same "Dimensions"-options as shown there. I'm guessing the add-on doesn't introduce new features in Blender only a kind of skin to organize and access features quickly(?).

So is it possible to restrict/constrain the movement of a Rigid Body - and how could that be done?

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You can do this with Rigid Body Constraints.

The 'Generic' constraint allows you to set up the constrains between two objects to set the amount the objects are allowed to vary from an Angular (rotation) and a Linear (position) point of view. By linking your 'Active' Rigid Body object to a 'Passive' one (that acts as the anchor) you can easily limit the motion.

The settings I used were as follows :

rb constraint

Here the limits on X and Y prevent it from moving in anything but the Z direction and the limits on Angle prevent it being rotated. Note how each is enable/disabled and the Lower and Upper limits set. In my case the Cube was the Active body and Sphere was passive to act as the anchor to it.

To set this up, simply select the two rigid bodies and select the Connect option, specifying to connect as contraint type 'Generic', then select the created empty and setup the constraint as shown above.

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  • $\begingroup$ Well this looks absolutely promising! Thanks for a fast and descriptive answer. Do I understand correctly that the passive object is not being used as pushing force but only as anchor? I can get it working when using a third object (active+animated) to push the cube (and the sphere as passive anchor, resting out of sight). $\endgroup$
    – morganF
    Mar 26, 2021 at 12:25
  • $\begingroup$ Yes - the passive one is purely an anchor and used as reference to constrain the active one. If you already have something static in your scene (such as a floor) then you can use that instead, providing it doesn't move or rotate. $\endgroup$
    – Rich Sedman
    Mar 26, 2021 at 12:44
  • $\begingroup$ Of course! This will make things much more clean. I HAVE a floor, naturally :) Thanks a bunch $\endgroup$
    – morganF
    Mar 26, 2021 at 13:59

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