Chapter 4 Sketching and Orthographic Projection

2 Links for Chapter 4 Sketching Shapes Sketching Procedures Orthographic Projection

3 Sketching Tools & Materials Soft lead pencil with H or HB lead Type of paper is not critical as long as the idea can be conveyed

4 Sketching Lines Create lines with short connected segments Keep lines light so they can easily be erased

5 Sketching Circles Trammel method –Mark the radius of the circle on the trammel –Place pencil on one point while holding the other point at the center of the circle –Rotate trammel around the center Hand compass method –Use your hand as the center and rotate paper

6 Measurement and Proportion Proportion of lines to each other are more important then the size of the sketch itself The first line sketched determines the scale of the drawing Make sure the direction and position of lines are accurate Use your pencil to establish measurements

7 Sketching Procedures Before sketching try to visualize the object Sketch very light lines of the outline Add details being careful to keep the proportion correct Darken in the desired lines of the final sketch Use a grid to create irregular shapes

8 Multiview Sketches Block out views and 45° line The 45° line is used to project lines from the top and right side view

9 Isometric Sketches Isometric sketches are a three-dimensional pictorial representation of the object Begin by drawing –Horizontal ground line –Perpendicular line –Two 30° lines

10 Isometric Sketches Determine best view for the front Set up isometric axes Sketch overall block Add details

11 Isometric Details Nonisometric lines are not parallel to one of the three original axes and are not true length Circles and arcs appear as ovals –Use the four-center method to construct –Be sure they lie on the proper plane

12 Orthographic Projection Any projection of features onto an imaginary perpendicular plane –Lines of sight are perpendicular to the plane –Objects are true size if they are parallel to the plane –Objects are foreshortened if they are not parallel to the plane

13 Multiview Projection In architecture, two-dimensional exterior drawings are referred to as elevations Use a glass box to help visualize the six views

14 Multiview Details Use the front, left side, right side, and back as elevations Top view is the roof plan Project circles and inclined lines using the 45° line projection method