Hold down Shift and, on the Dimensioning tab, click one of the dimensioning buttons depending on the type of dimension you want to create: Horizontal : Create a dimension in the x direction by picking the points to be dimensioned. X depends on the current UCS.
Vertical : Create a dimension in the y direction by picking the points to be dimensioned. Y depends on the current UCS.
Perpendicular : Create a dimension perpendicular to a line you define by picking two points to set the direction of the dimension line, and then picking the points to be dimensioned.
Orthogonal : Create a dimension in either the x or y direction by picking the points to be dimensioned. Tekla Structures uses the direction of the larger overall distance. X and y depend on the current UCS.
Curved dimension, orthogonal reference lines : Create curved dimension with orthogonal reference lines by picking three points to define the arc and then picking the points to be dimensioned. The dimension text on the line can be either a distance or an angle value.
Curved dimension, radial reference lines : Create curved dimension with radial reference lines by picking three points to define the arc and then picking the points to be dimensioned. The dimension text on the line can be either a distance or an angle value.
Free : Create a dimension parallel to a line between any two points you pick.
COG : Indicate the location of the center of gravity (COG) in single-part, assembly, and cast unit drawings by creating COG dimensions and adding a COG symbol at the center of gravity. You can also create COG dimensions in section views.
Parallel : Create a dimension parallel to a line you define by first picking two points to define the direction of the dimension line and then picking the points to be dimensioned.
Radial : Create radial dimension by picking three points to define the arc and pick a position for the dimension.
Angular : Create angular dimension by picking the vertex point and two points to define the angle. Pick the side to place the dimension.