Ruler

Selecting the icon 2D or 3D coordinate axes will be displayed.
  Initially, the Ruler will start in 2D Mode. You can switch to 3D Mode using the context menu.

You can move the coordinate axes origin using the left mouse button. The new position is stored until you change it again, close the 3D shape, or terminate the session.
The current measure unit is displayed at the ruler and can be set in Tools > Options > Parameters and Measure on the Units tab.

The ruler can be displayed in black or white color. To ensure visibility of the ruler also with very bright or dark background colors, it is automatically set to the color with higher contrast to the background color.
 

Manipulator Snap
  The ruler manipulator has a snap function allowing to position the ruler origin onto a geometry element.
Depending on the element type, the manipulator is displayed with the following red marker after having snapped onto an element:
  • large dashed circle on an underlying point,
  • small square with an x symbol on an underlying curve,
  • small rhomb with an x symbol on an underlying surface.

After the manipulator has snapped onto an element, you can reduce the manipulator motion to the element by pressing and holding the shift key. Releasing the shift key while the left mouse button is pressed will reposition the ruler origin to the mouse position.
 

Contextual Menu
  Right clicking the origin of the coordinate axes activates the contextual commands:
  • Edit: The dialog box Edit Position is displayed in which you can define the following options:


    • Components: The position of the coordinate axes origin can be specified numerically.
    • Position: The position of the coordinate axes can be selected graphically. Click onto the field in the dialog box and select in the graphics area a point as new position.
  • Delete: Blanks the ruler.
  • 2D Mode: Displays 2D coordinate axes parallel to the screen coordinate axes.
  • 3D Mode: This manipulator also consists of two axes. The axis with the smallest angle to the view plane normal is hidden.
    Unlike the 2D mode, the axes are aligned to the model coordinate system and their origin is identical with the origin of the model system. The 3D Ruler axes scale show the absolute distance from the origin of the model coordinate system.
    The 3D ruler has two additional manipulators to move the ruler along the corresponding axis.