Which constraint type ?

[Lylith]

I can not figure out how to limit the movement of two blocks relative to each other only along the axis Y. And without rotation relative to each other.

I tried different types, but only got this.

[Lylith]

Another additional question.
How to fix the body rotated at some angle, with two PivotJoint ?
I am creating a body, turn it to the desired angle, add a Pivots. The body pushes and rotated by an angle 0.
*Blue shows the original position, before adding Pivots.

[slembcke]

I can not figure out how to limit the movement of two blocks relative to each other only along the axis Y. And without rotation relative to each other.

Use a groove joint for the vertical motion and a gear joint with a ratio of 1.0 for the rotation.

How to fix the body rotated at some angle

Use a gear joint again with a ratio of 1.0. Use the phase property to set the angle between them.

[Lylith]

How did you know that it works!?
Thank you very much. You saved a lot of my time. I left a detailed study of Gear on later. I hade association: gear- mean movement.

[slembcke]

Yeah, I guess it's not obvious, but a gear joint with a ratio of 1.0 means both objects rotate at the same speed. It basically locks their rotation together.