CE En 112 Engineering Drawing with CAD Application

CE En 112 Engineering Drawing with CAD Application Chapter 2: Sketching and Text (Lecture A)

Lecture Outline (Chap. 2) • Technical sketching (2.1) • Sketching technique (2.2) • Proportions and construction lines (2.3) • Introduction to projections (2.4) • Multiview sketching technique (2.5) – next Monday • Multiview sketches (2.6) – next Monday • Lettering (2.8) • Next class

Objectives • Define technical sketching (p.17 of Ch.2) • Understand how sketching integrates into the design process (p.18 of Ch.2) • Identify and define two types of sketches (pictorial & multiview – p.18 & 19 of Ch.2, p.32 of Ch.1) • Create a design sketch using pencil • Identify and use sketching tools (p.19 of Ch.2) • Use grid paper to create sketches (p.20 of Ch.2) • Lay out a sketch using proportions (Section 2.5 of Ch.2) • Understand the difference between pictorial and multiview projection (Section 2.4 of Ch.2) • Learn about a perspective sketch, an isometric sketch, an oblique sketch, and a multivew sketch (Section 2.6 of Ch.2) • Identify the types and precedence of lines (Section 2.5 of Ch.2) • Follow good hand-lettering practice (Section 1.16 of Ch.1) Note that multiviews will be covered next Monday in detail.

Technical Sketching (2.1) • Technical Sketching is the process of producing a rough, preliminary drawing representing the main features of a product • Generally less finished, structured, or restricted, and less time for its creation • Tools include pencil, eraser, and paper (grid or blank) Means to create technical drawings Level of detail of freehand technical drawing

Technical Sketching (continued) Rough sketch Multi-view sketch Shaded sketch (Illustration) Pictorial sketch

Technical Sketching (continued) • Technical sketches: used extensively in the first (ideation) stage of the design process to explore and solidify design ideas that form in the mind’s eye

Technical Sketching (continued) • Transforming your ideas into tangible graphic images serves both as a permanent record of those ideas and as a means of encouraging creative thinking • What’s the difference between the two figures below?

Sketching Technique (2.2) • Sketching is based on the interactive process of seeing, imaging (forming structure and meaning of visual data), and representing (creating sketches of what our mind sees). The goal of technical sketching is simplification.

Sketching Technique (con’t) • What do you see?

Sketching Technique (2.2) • Practice Exercise 2.1 (Chapter 2, p. 21, [p.77]) • Our perception is not limited to what we can see. Images often appear spontaneously in response to a memory recall. In this exercise, read the words and see if visual images are created in your mind’s eye. • Your bedroom where you grew up as a child, or the street you lived on. • A close relative, a famous actor, or a close friend from high school. • A basketball sitting at center court on your high school gym floor. • Your response to these written prompts is an example of your visual memory. You are thinking visually, which is a very powerful way of thinking when designing.

Sketching Technique (con’t)

Proportions & Construction Lines (2.3) • Proportion: • The ratio between two dimensions of an object • Represented by a series of preliminary (construction) lines, drawn light and fast, which may or may not represent the locations of the final lines in the sketch • The relative proportions of the primary dimensions of an object is more important than their actual physical sizes *Note: If a drawing doesn’t look or feel right, it probably isn’t

Proportions & Construction Lines (con’t) • Example of relative proportions: Standard proportions for the United States flag

Proportions & Construction Lines (con’t) • Creating a proportioned sketch: • Step 1: Gage the proportion of the overall size of the object. Lightly draw construction lines to create a bounding box • Step 2: Inside bounding box, draw major features of object • Step 3: Continue to draw bounding boxes until all features are represented • Step 4: Begin sketching the final line work (dark) Comic book writers may distort proportions.

Introduction to Projections (2.4) • Projections: developed to represent 3-D images on 2-D media • Four basic types of projections: • Multiview • Axonometric • Oblique • Perspective • B, C, and D are pictorial because they represent the object as a 3-D form More to come in future lectures…

Multiview Sketching Technique (2.5) – (Slide 18 through 24 to be covered next Monday.)

Multiview Sketching Technique (con’t) • Hidden line conventions must be followed in multiview sketching • Review these conventions and we will discuss them further in later lectures

Multiview Sketches (2.6) One-view, two-view, three-view sketches depending on the complexity of the object. Refer to the text for the steps in determining which to use – we will also discuss more in later lectures…

Multiview Sketches (con’t) Three image planes

Multiview Sketches (con’t) • Visualization Techniques: Object – Image plane – The eye of the reviewer relationship Horizontal, vertical, and depth

Multiview Sketches (con’t) We will cover this topic later. Three types of faces: 1. Normal 2. Inclined

Multiview Sketches (con’t) We will cover this topic later. 2. Inclined Inclined vs. Oblique faces: Can you tell the difference? 3. Oblique

Lettering (2.8)

Lettering (con’t) Lettering dimensions: Examples of lettering:

Next Monday Class • Read Chapter 2, starting Section 2.4 in page 29 [p. 85]. • Open up the lecture link to see the sections that will be covered next Monday.

CE En 112 Engineering Drawing with CAD Application