| A | B |
|---|
| Annotation | Explanatory notes added to a drawing. |
| Centerline | A line type that is used to indicate the axis of symmetry for a part or feature. |
| Construction Line | Thin lines that serve as guides while sketching or drawing. |
| Depth | The distance from front to back. |
| Diameter | A straight line passing from side to side through the center of a circle or sphere. |
| Dimension | A measurable extent, such as the three principal dimensions of an object of width, height, and depth. |
| Dimension Line | Thin lines capped with arrowheads, which may be broken along their length to provide space for the dimension numerals. |
| Extension Line | A thin solid line perpendicular to a dimension line, indicating which feature is associated with the dimension. |
| Height | The measurement of someone or something from head to foot or from base to top. |
| Hidden Line | A line type that represents an edge that is not directly visible because it is behind or beneath another surface. |
| Isometric | A form of pictorial drawing in which all three drawing axes form equal angles of 120 degrees with the plane of projection. |
| Leader Line | Lines that are thin and used to connect a specific note to a feature. |
| Line Conventions | Standardization of lines used on technical drawings by line weight and style. |
| Line Weight | Also called line width. The thickness of a line, characterized as thick or thin. |
| Location Dimension | Dimensions that show the exact location of parts of an object. |
| Object Line | A heavy solid line used on a drawing to represent the outline of an object. |
| One-Point Perspective | A method of realistic drawing in which the part of an object closest to the viewer is a planar face, and all the lines describing sides perpendicular to that face can be extended back to converge at one point, the vanishing point. |
| Orthographic Projection | A method of representing three-dimensional objects on a plane having only length and breadth. |
| Perspective Drawing | A form of pictorial drawing in which vanishing points are used to provide the depth and distortion that is seen with the human eye. |
| Plane | A flat surface on which a straight line joining any two points would lie. |
| Radius | A straight line from the center to the circumference of a circle or sphere. |
| Scale | A proportion between two sets of dimensions used in developing accurate, larger or smaller prototypes, or models of design ideas. |
| Size Dimension | Placed directly on a feature to identify a specific size or may be connected to a feature in the form of a note. |
| Sketch | A rough drawing representing the main features of an object or scene and often made as a preliminary study. |
| Three Dimensional (3D) | Having the dimensions of height, width, and depth. |
| Thumbnail Sketch | A preliminary visual of a possible idea for a design. Most thumbnail sketches are not full-size and have little detail. They are intended to quickly explore possible alternative designs. |
| Two Dimensional (2D) | Having the dimensions of height and width, height and depth, or width and depth only. |
| Two-Point Perspective | Realistic way of drawing objects in three dimensions using a horizon line, a key edge, and two vanishing points. |
| Vanishing Point | A point in space, usually located on the horizon, where parallel edges of an object appear to converge. |
| Views | The six mutually perpendicular directions any object may be viewed are top, front, right-side, rear, left-side, and bottom. |
| Visualize | To imagine the visual form of an object or situation that one cannot see. |
| Width | The measurement or extent of something from side to side. |
