Sketching Practice. Sketching “One picture is worth a thousand words.”

Sketching Practice

Sketching“One picture is worth a thousand words.”

• The main purpose of sketching is to convey ideas.

• Engineers have to use sketches to brainstorm ideas, as well as, to show others what they are working on or what should be designed.

• Sketches are also used to document measurements from the field before they are produced as solid models on the computer.

Purpose

Sketches used in Engineering

• Pictorial – shows object in 3D formIsometric

• Orthographic – shows object in 2D formMultiview

Perspective

Pictorial Sketches

• Show shape of object

• Show height, width, and depth

• Common types:– Isometric– Perspective

Thumbnail Sketches

• A quick way of getting an idea onto a sheet of paper

• Usually small but made in proportion

• Sketch with a light touch on the pencil; darken when in final stages.

Irregular Shapes

• Size: Length, width, height,

distance. How big is the object

you are sketching?

• Proportion: If two objects are

five feet apart in real life, then

those two objects must appear to

be five feet apart in your sketch.

TWO TYPES

• Irregular Shape – Block Method

• Irregular Shape – Frame of

Reference

Perspective

• Perspective is a way to draw that shows a view of the object in the most realistic way.

• Vanishing points are used to guide the lines in the object to the horizon line or the horizontal line you see at your line of sight.

One-Point Perspective

One-Point Perspective

• All lines in the depth project to one point (the vanishing point).

• The location of the vanishing point is based on your line of sight.

• Copy this one-point perspective sketch onto your activity. Label the front, top, and right side.

Vanishing Point (VP)

One-Point Perspective

All lines in the depth projectto one point (vanishing

point). The location of the vanishing point is based

on your line of sight.

Copy this 1-pointPerspective sketch

on your drawing paper.

Two-Point Perspective

Two-Point Perspective

• In two-point perspective, the width lines converge on one vanishing point (VP1), and the depth lines converge on the other vanishing point (VP2).

• Copy this two-point perspective onto your activity sheet. Label the top, front, and side.

VP1 VP2

Two-Point Perspective

In two point perspective the depth lines converge on onevanishing point (VP2) and thewidth lines converge on theother vanishing point (VP1).

Copy this two-pointPerspective sketch

on your drawing paper.

3D Sketching Techniques

Isometric Grid Paper

Isometric Sketch

• Width and depth lines are drawn at 30° from the horizon line.

• One view shows height, width, and depth.

Thumbnail Isometric Sketch

Copy and label this cube on your isometric axis.

Isometric Sketching

Width and depth linesare drawn at 30 degrees from

the horizon line.

Note: one view shows Height, width, and depth.

Copy and labelthis cube on yourisometric axis

Isometric Sketching

Copy this sketch ontoyour 2nd isometric

axis.

Follow the directions in Activity 3.1 The Language of Sketching Sketch Group 2 Thumbnail isometric sketching.

Isometric Thumbnail Sketch

• Additive and Subtractive 3D sketch

• Follow the steps in your activity to complete this drawing on the isometric graph paper.

Orthographic (Multiview Drawings)

Multiview SketchingThe arrows represent the line of sight associated

with each view.

Note how the viewsare oriented. Each view is

adjacent to the other asif they were unfolded

from a 3D shape.

Orthographic (Multiview) Sketching

• An orthographic sketch is used to show true size and shape.

• Each view is adjacent to the other as if unfolded from a 3D shape.

• Notice the top view is directly above the front with the right side view directly to the right of the front.

Orthographic (Multiview) Sketching

• Copy this orthographic sketch onto your activity sheet. Label the top, front, and right side.

• Don’t forget the hidden lines.

Multiview SketchingDraw this object (Multiview).

Multiview SketchingDraw this object (Multiview).

Multiview SketchingDraw this object (Multiview).

Multiview SketchingDraw this object (Multiview).

Multiview SketchingDraw this object (Multiview).

Orthographic – View SelectionCharacteristics for selecting the front view

• Best shape & details

• Longest dimensions

• Fewest hidden lines

• Most natural position

Which view do you think should be the front?

1 2 3 4 5

Multiview SketchingCopy the multiviewsketch below on to

your worksheet

Precedence of Lines

• Object lines exist over hidden and center lines.

• Hidden lines exist over center lines.

Example 1Object line over

hidden lines

Example 2Object line

over center line