CAD stands for “computer aided design.”
The term “CAD” is an acronym for computer aided design, which refers to the broad approach that many architects, engineers and other designers use to produce the high-precision graphics needed for their work. Learning to use two dimensional (2D) CAD includes learning the component skill of 2D navigation, so you can inspect your drawing from different viewpoints. Another component skill in 2D design is creating the initial primitive shapes that your final drawing will be based on. These shapes typically take the form of rectangles or other polygons.
1. Open your CAD application and select its polyline tool, which you’ll use to construct the facade of a triumphal arch from classical Roman architecture.
Polylines are chains of curved or straight segments that connect a set of points you define.
2. Click near the lower left corner of your application’s main drawing area to plot the arch’s bottom left point. Drag directly upward until the arch’s height is roughly one-eighth the height of the drawing window. Click the mouse to finish the first segment and begin the second.
3. Choose the option to create an arc instead of a line segment, for the next segment of the arch. This option will likely be available as a right-click pop-up menu in your program. If it is not, consult your program’s documentation.
4. Move the mouse right for roughly half the span of your first (straight) segment, to define the arc’s diameter. Click the mouse to complete the arc.
5. Re-select the option for straight-line segments, then drag the mouse directly downward until the mouse pointer reaches the bottom point of the first segment you plotted. Click the mouse to finish the segment.
6. Release the polyline tool (by pressing “Escape” or “Enter”), noticing that you’ve defined the interior portion of the arch.
7. Select the rectangle tool, then draw a rectangle that surrounds the arch interior. Size the rectangle so that the distance from its left edge to the left edge of the arch’s interior is slightly less than the radius of the arc you made in step 4. Position the rectangle’s top such that the distance from this top to the top of step 4’s arc is equal to the distance referred to in the previous sentence of this paragraph.
8. Prepare to delete the portion of the rectangle that’s inside the interior arch: Select your program’s mode for editing rectangles, then add two more vertices, where the rectangle intersects the arch’s interior polyline (which you completed in step 5).
9. Complete the triumphal arch by selecting and deleting the edge created by the new vertices you plotted.