What is Gizmo in AutoCAD & 3D Studio MAX?

Great Participation for experts, All answers are very comprehensive.

Specially thanks to Mr. أسامة يسرى أحمد for very detailed Answer. 

It is a transformation tool used in AutoCAD3D. Its special because now using this you do not have to lock the axes keys in the software and can now easily mover from X, Y to Z axis

When you create or select an object, you should see an axis tripod icon. You should see the new transform gizmo when you select an object with one of the Transform tools:

- Select and Move

- Select and Rotate

- Select and Scale

A missing axis tripod icon or transform gizmo can manifest in two ways.

• The Axis Tripod Icon is visible but the Transform Gizmo is not.
• The Axis Tripod Icon -and- the Transform Gizmo are not visible.

Most commonly, this situation starts by accidentally turning off the transform gizmo and is compounded by turning off the Show Transform Gizmo in the Views menu.

Solution:

Solution

By default, the transform gizmo in 3ds max is assigned a keyboard shortcut - X. Since the transform gizmo setting is normally active, pressing the 'X' key toggles the transform gizmo off and on.

If you see the axis tripod icon but not the transform gizmo when an object is selected with one of the Transform tools, simply press the X key. You should see the transform gizmo again.

If you don't see either the transform gizmo or the axis tripod icon, the Show Transform Gizmo setting in the Views menu is probably turned off.

1. Select an object using the Select and Move tool.
2. Open the Views menu.
3. Click on Show Transform Gizmo.

   You should see the axis tripod icon and the transform gizmo. If you only see the axis tripod icon, go to step4.

4. Press the X key.

    

   Now you should see the transform gizmo superimposed over the axis tripod icon.

The transform gizmo can also be toggled on and off or adjusted from the Customize menu > Preferences dialog > Viewports tab as shown below.

Default settings for the transform gizmo.

If you toggle off the transform gizmo and/or turn off the Show Transform Gizmo setting and exit 3ds max, those program changes get written to 3dsmax.ini file. That means the next time you start 3ds max, those settings will remain as you set them. You can change the settings manually by editing the 3dsmax.ini in a text editor like Notepad.

• Changes made to the Show Transform Gizmo are reflected on the ShowAxisIcon= line.
• Changes made to the Transform Gizmo toggle are reflected on the TransformGizmo= line.

If either entry is set to 1, it is active. If the entry is set to 0, it is inactive.