The 3D Markup Dimension dimension commands are called from either the Linear, Radial, Angular, or and 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 modelpoints, red dots appear on the model that indicate where selections can be made. (If you do not see the red dots, you may want to go to the 3D Viewer Settings page and select the Vertices visible Points Visible on pickingPicking check box.) A cross-hatch indicates
Red 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 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 the line or circle highlight will appeararc is highlighted.
3D Markup Dimensions
Calculate menu (found on the Assembly pane):
Calculations
It's easy to determine the volume, surface area, center of mass, bounding boxes, and weight of your model or part: Right-click an item listed in the assembly tree or on a model or part in the viewport to view the assembly context menu. Select Calculate, then select a function. See Assemblies and Parts in a 3D Scene and Assembly Context Menu for more information.