Color by Axis is a Blender add-on that allows you to check whether the edges of an object are aligned with the X, Y or Z axis, by creating a color overlay.

⚠ This add-on is still a work in progress. Currently tested on Blender 3.0 and above.

Download the source code as "zip" and install it like any other Blender add-on.

The add-on will create a Panel in the N-Panel, called Color by Axis. Here is an explanation about the main items:

• Color by Axis checkbox:

  • Activates the overlay over any selected object.
  • Once created, it will allow will to navigate the viewport, but will be turned off as soon as you type or click.

• Axis type option:

  • GLOBAL: Compare your object's edges with global axis.
  • LOCAL: Compare your object's edges with its local axis.
  • REFERENCE: Compare your object's edges with a selected reference object. If no reference is provided it will work as LOCAL.

• Reference object:

  • Select the object which will be used by the REFERENCE axis type.

Note: the colors of the overlay are attached to Blender's default theme, for consistency. If you want to change this, you have to change preference > themes > user interface > axis & gizmos colors > Axis x, y, z

• Add a default cube, make a copy and rotate it 30 degrees in Z axis.
• Add an empty and rotate it 30 degrees in Z axis.
• Select both cubes and enter "Edit Mode".
• Click the checkbox "Color by Axis" in the N-panel. The edges of the cube will be colored according to the global axis that they are parallel to.

• If "LOCAL" Axis Type is selected, it will color the edges based on the local coordinates of the objects.

• If "REFERENCE" Axis Type is selected, choose the empty object as reference. It will color the edges based on the local coordinates of the reference object.