The 3D Markup Dimension commands are called from either the Linear, Radial, Angular, or Smart Edge Dimension menus located on the 3D Document Toolbar.
Selecting a Point
A 3D design is built from lines, triangles, and other polygons. Points generally indicate intersections between the elements that underlie the 3D design. When you choose a command that requires you to select a point, the pointer appears as an arrow with a small "x" at the tip when over the Viewport. Red dots designate available points on the model. (If you do not see the red dots, you may want to go to the 3D Viewer Settings page and select the Vertices visible on picking check box.) A cross-hatch indicates 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 you to select an edge or arc that already exists on the model. When the pointer is properly positioned over an edge or arc, a line or circle highlight will appear.
3D Markup Dimensions
Calculate menu (found on the Assembly pane):
Volume - Measures the volume of a part. How...
Surface - Measures the surface area of a part. How...
Center of Mass - Lists the X, Y, and Z coordinates of the center of mass of a part. How...
Extent Box - Draws a box around a part and measures the part along the X-, Y-, and Z-axes. How...