For linear dimensions (orthogonal, parallel, and rotated), you can define the dimension by selecting two points (manually), or you can select a segment or entire object to dimension.
Segment and Entity modes are options on the local menu, as well as on the Inspector Bar while using a linear dimension tool. Once you have selected a dimensioning mode, the mode remains in effect until changed.
Tip: If you generally prefer one of the dimensioning modes over the others, you can save it in a drawing template. To do this, use File / Save As to save the file as a .tct file (TurboCAD Template). Place the template file in the "Template" folder of the TurboCAD root directory. Then when you want to open the template, use *File / New, and select New from Template.
In Segment mode, select any line segment, and the dimension between endpoints is created.
Segment mode - orthogonal dimension
Segment mode - parallel dimension
In Entity mode, select an object, and the largest dimension in the specified direction is created. This is useful for dimensioning objects like polylines, polygons, rotated rectangles, etc.
Entity mode - orthogonal dimension
Entity mode - parallel dimension