How to do a 3D rotation in AutoCAD?

There are several commands that allow you to perform a 3D rotation in AutoCAD:

• ROTATE3D: command similar to the command that allows you to perform a 2D rotation;
• 3DROTATE: allows you to perform a rotation using a "gizmo";
• ALIGN and 3DALIGN: allow you to align objects onto a plane.

There's not much to say about the ROTATE3D command. You define the rotation axis, most often by selecting two points. Then you enter the angle. As a reminder, by default in AutoCAD, angles use the trigonometric direction. So if for example you rotate around the Z axis, the positive direction is when you go from the X axis to the Y axis. If you rotate around the X axis, the positive direction is when you go from the Y axis to the Z axis. Finally, if you rotate around the Y axis, the positive direction is when you go from the X axis to the Z axis.

The 3DROTATE command allows you to perform a rotation using a "gizmo". A gizmo is a symbol that appears on the screen. For rotation, it looks like this:

These are the red, green, and blue rings. By clicking on the red ring, you choose the red axis which corresponds by default to the X axis. To memorize the color/axis correspondence, it's simple, it's like for a screen: RGB (red, green, blue) corresponds to XYZ (X axis, Y axis, Z axis).

By right-clicking, you can display a context menu that allows you to reposition the gizmo. But be careful. If you try, you may realize that it doesn't work. In fact, to use gizmos, you need to switch to a 3D visual style. Indeed, in AutoCAD, by default you are in the 2D Wireframe visual style. Before launching ROTATION3D, you need to switch to one of the 3D visual styles like Hidden, Realistic, or simply Wireframe. In fact, only 2D Wireframe is a 2D visual style, all the others are 3D (they actually use another graphics system optimized for 3D).

Finally, we have the ALIGN and 3DALIGN commands that allow you to align objects onto a plane. For those who know Inventor, it's a bit like a flush constraint.

It works with three pairs of points. For example here, we started by selecting the midpoint of the text and the midpoint of the destination plane (in red). Then the left midpoint of the frame and the left midpoint of the destination plane (in yellow). Finally, the top midpoint of the frame and the top midpoint of the destination plane (in green). AutoCAD then calculates the rotation so that the points match.

The 3DALIGN command works the same way, except that you start by selecting three points on the objects to align, then the three points on the destination plane. This allows you to have a preview of the rotation before applying it.

Note that the ALIGN command also works in 2D, with two pairs of points.

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