Orthographic Projection, multi-view drawings, & Precedence of lines

ORTHOGRAPHIC PROJECTION, MULTI-VIEW DRAWINGS, &

PRECEDENCE OF LINESNorth Carolina State University

Spring 2013

What You Will Learn:

Define Orthographic Projection.

Correctly label the placement of the six standard

views of an object drawing.

Identify which views are needed when creating a

multi-view drawing of an object.

Create a multi-view drawing with the correct views

from a given object.

Identify different types of lines used for drafting.

Identify which line types have precedence over others.

Create multi-view drawings using different line types.

SECTION 1:

ORTHOGRAPHIC PROJECTION & MULTI-VIEW DRAWINGS

Orthographic Projection

Orthographic Projection: (n) a parallel projection technique that creates a 2-D image of 3-D objects or structures on an image plane perpendicular to the lines of sight.

In The U.S. we use a method called Third Angle Projection

Used to represent all aspects of a 3-D object by only using 2-D drawings

Glass Box Method View each object

as if it were in a glass box.

When unfolding the box you have the 6 views of projection.

The 6 Views of Projection

Top – Looking down on an object (birds eye view)

Front – ALWAYS the most descriptive Right Side – To the right of the front view Bottom – opposite of the top Left Side – opposite of the right Back – opposite of the front

Proper Layout of a Multi-View Each view has a specific location as to

where it is placed in reference to others.

Creating a Multi-View Drawing Only use the views necessary to

visualize the full object. (Typically: top, front, right side)

Sometimes only two views are necessary such as when drawing a cylinder

Examples

Examples

INCORRECT CORRECT

Guided Practice: Create a multi-view

drawing of this object.

Label each view of your drawing.

Solution:

Guided Practice: Create a multi-view

drawing of this object.

Label each view of your drawing.

Solution:

Independent Practice: Create a multi-view drawing of the following two

objects. Label each view of your drawings.

Solution 1:

Solution 2:

SECTION 2:

LINE TYPES &PRECEDENCE OF LINES

Visible Lines:

Thick and Bold Often called construction lines or object

lines Used for the outer edges and visible

features of an object.

Hidden Lines:

Thin, dashed line Used to show hidden features within an

object which can not be seen from the outside of the object.

Center Lines:

Thin lines with alternating long and short dashes.

Show the center of both visible and hidden circular features such as holes, cylinders, etc.

Precedence of Lines

Precedence of Lines: The order in which different line types appear in an drawing based on importance.

Precedence of Lines:

Example:

Guided Practice: Create a multi-view

drawing of this object.

Label each view of your drawing.

Include visible, hidden, and center lines

Solution:

Guided Practice: Create a multi-view

drawing of this object.

Label each view of your drawing.

Include visible, hidden, and center lines

Solution:

Independent Practice: Create a multi-view drawing of the following two

objects. Label each view of your drawings. Include visible, hidden, and center lines

Solution 1:

Solution 2: