Move an ob­­­ject onto a rectangular wall and see how the object rotates around its lengthwise axis so that it is always parallel to the wall.

Align objects to external walls.

If you want to repeat this command, select the object and, after you have moved the mouse pointer to the small black cube of the coordinate system, 

its initial colour changes to yellow. 

Keep the left mouse button pressed and align the object to an external wall of your choice.

Selected object.

Click the black cube: its initial colour changes to yellow.

Keep the left mouse button pressed and align the object.

Whether the object turns the right way or not will depend on where the origin point and the object axis of the object are defined. 

Click on the object, press the right mouse button and select  “Use object axis” . 

If the zero point is on the rear side and the Y-axis is parallel to that part of the object, as it should be, then there will be no problem.

Object axis related to the scene.

Press the right mouse button and select Use object axis.

Note:  The automatic object rotation works for all objects in 2D and 3D. 

You can move objects along rectangular external walls using the object axis.