| 摘要 |
A computer aided design (CAD) system (10, 10') projects or otherwise displays a drawing image onto a working surface (36). The displayed image and working surface are large enough to view the entire CAD-generated drawing with sufficient resolution, e.g., greater than four millon pixels, to permit working directly on the drawing surface, using familiar manual drafting or writing techniques, without having to magnify or enlarge the drawing image. The invention allows the desirable features of a CAD system, such as meory recall of commonly used drawn elements, scaling, rotation, indexing, etc., to be freely used, but without the annoyance, frustration, and inefficiencies of having to constantly change the magnification and location of the drawing, as is required using conventional CAD systems. Display of the drawing image is realized, in a preferred embodiment, through the use of multiple rear projection tubes (38) mounted behind the drawing surface in an X-Y grid. Data entry is realized, e.g., using a light pen (16, 46) on the drawing surface and/or a touch sensitive screen (44, 56) overlaying the drawing surface. |
