SKETCHING Rough Sketches-“rough” is not used to describe the quality of the drawing. Refined Sketches-design ideas that are developed by merging ideas from two or more rough sketches into a refined sketch. The new idea may not look anything like the original rough sketches.

Detailed Sketches are used to build models of the products or structures –size information explains the overall dimensions of the object, or the size of the features on an object –location information gives the position of the features within the object –geometry information describes the geometric shape or relationship of features on the object.

Oblique sketches front view as if a person was looking directly at it. sides and top extend back from the front view parallel lines that are generally drawn at 45  to the front view two types are cavalier and cabinet. –cavalier oblique drawing causes the sides and top to look deeper than they are –cabinet oblique drawings are drawings that project back from the front to one-half their original length.

Isometric Sketches Isometric means equal measure Angles formed by the lines at the upper right corner are equal – each is 120  The object is shown as if it were viewed from one corner

Perspective Sketches show the object as the human eye would see realism is obtained by having parallel lines meet at a distant vantage point. –(one/two point perspective) most realistic of the three sketches.

Detail (Working) Drawings multi-view method one or more views of the object in one drawing: a top, right side, and front view are shown. orthographic projection –Front view is drawn in the lower left quadrant of the paper. –Projection lines are extended to the top and right

CAD (Computer-Aided Design) CADD (Computer-Aided Design and Drafting)

Advantages of CAD Speed Quality Ease of modification Cost 2D-3D

3D Systems - Stereo Lithography Apparatus (SLA) produces full-size, 3D models using plastic or chalk materials directly from CAD drawings by laying down

CAD Terminology Commands Entity Grids Snap Grids Rotation Drag and Move Dimensions Pan Zoom Windows Rotation Scale Lines Points Planes

Cartesian Coordinates System a method of graphical point location that allows precise positioning of entities on the drawing surface Coordinate pair (X, Y) 3-D Coordinates (X,Y,Z) Absolute Coordinates Relative Coordinates