The 3D Markups Dimension commands are called from either the Linear, Radial, Angular, or Smart Edge Dimension menus on the 3D Document Toolbar
Selecting a Point
A 3D design is built from lines, triangles, and other polygons. Points are the intersections between the figures that underlie the 3D design. Red dots designate available points on the model. (If you do not see the red dots, go to the 3D Viewer Options page and select the Points Visible on Picking checkbox.) Crosshairs indicate when the pointer is properly positioned over a point. A yellow dot indicates that you have successfully selected a point.
Selecting an Edge or Arc
Some 3D markup dimension commands, such as Edge Length and Arc Diameter, require that you select an edge or arc that already exists on the model. When the pointer is properly positioned, the edge or arc is highlighted.
Related Topics
Working with Linear Measurements