GC 120 Final

What is the standard angle of projection in the United States? Describe the locations of the planes of projection, observer, object and projection lines in 1st and 3rd angle projection

3rd angle 1st angle - observer, object, projection plane. 3rd - observer, projection plane, object

What is a miter line? When would you use one?

A construction technique that allows depth dimension to be projected between top and profile views

What is a detail drawing? What is an assembly drawing? What is included in each?

A detail drawing is a dimensioned, multiview drawing of a single part An assembly drawing shows how each part of a design is put together. An assembly drawing normally consists of all the parts, a parts list or bill of materials, leader lines with balloons, assigning each part a detail number, in sequential order and keyed to the list of parts in the parts list, and machining and assembly operations and critical dimensions related to these functions.

What are the different methods for defining a sweep distance?

A dimension value (linear or angular), sketch, or feature edge

Chord

A straight line joining any two points on the circumference

What is an extension line? dimension line? leader line? What are the standards for the way they appear on drawings

A thin, solid line perpendicular to a dimension line that indicates which feature is associated with the dimension. A dimension line is A thin, solid line that shows the extend and direction of a dimension. A leader line is a thin solid line used to indicate the feature with which a dimension, note, or symbol is associated. Arrows are placed at the ends of dimension lines to show the limits of dimension. Arrows are usually about 3 mm long and should be one third as wide as they are long. For extension lines, there should be a visible gap of 1 mm between the feature's corners and the end of the extension line. For the leader line, it is drawn at an angle that is terminated with an arrow touching the part or detail

What organizations develop standards and conventional practices for engineering & technical graphics?

ANSI & ISO

Construction Geometry

Any geometry created as part of the CAD modeling process that does not represent actual part geometry. Examples are workplanes, axes, or points used to locate geometry in a solid model

Major arc

Arc measuring at least one half the circumference of the circle.

minor arc

Arc measuring less than a semicircle

Describe the following types of pictorials: anonometric, perspectives, and oblique

Axonometric projection is parallel projection technique used to create a pictorial drawing of an object by rotating the object on an axis relative to a projection. Perspective projections are pictorial drawings used to represent 3-D forms on 2-D media. Such drawings create most realistic representations of objects. Oblique projection is parallel projection where projectors are perpendicular to each other but not perpendicular to projection plane. In oblique only front face is seen in its true shape.

What are the differences and similarities between constructive solid geometry modeling and constraint-based modeling? What are the different types of Boolean operations related to 3D modeling?

CSG modeling Allows a modeler to create a complex surface or object by using Boolean operations to combine objects. Critical area is where places overlap. CB modeling Creating a dynamic model by having the model defined as a series of modifiable features. Each feature can be linked to other ones or made independent so they can be updated as design requirements change Union, Difference, Intersection

Bidirectional Associativity

Changes in either 3-D modeling data or supporting application will affect the other.

Parent-child relationships

Child feature is dependent on existence of parent feature

What is a Cartesian coordinate system? How are the axes related to one another?

Common coordinate system in math and graphics that locates positions of geometric forms in 2-D and 3-D space. Axes are perpendicular to one another.

Assembly Modeling

Components are brought together to define a larger, more complex product representation

Feature Tree

Computer interface that is common to most constraint-based modelers. It lists the geometric features in the order in which they are interpreted by the modeler.

Solid Model

Consists of information about what is on the inside of a 3-D model as well as information about the surface of an object

What is contour dimensioning? ???????What other general rules should one follow when dimensioning an object?

Contour dimensioning is when the contours or shapes of an object are dimensioned in their most descriptive view

What is the difference between convergent and parallel projection? List some different types under each category

Convergent requires that the object be positioned a finite distance and viewed from a single point. Parallel projection requires that the object be positioned at infinity and viewed from multiple points on an imaginary line parallel to the object. Orthographic project is parallel projection where the plane of projection is positioned between the observer and the object and is perpendicular to the parallel lines of sight

How are the arrowheads on the cutting-plane related to the view in section? What other types of lines are associated with sectional views?

Cutting plane line section lines, center lines, object lines

Degrees of Freedom

Describes the strength of a relationship between components. Less degrees means more of an established geometric relationship

What is the difference between an isometric drawing and an isometric projection?

Drawing produced using a scale of .816 is isometric projection is true representation of the object. If drawing is produced using full scale, it is called an isometric drawing.

What are the different types of sectional views?

Full, partial, half, revolved, removed, etc

What is a global or world coordinate system? What is local or relative coordinate system? How are they used in the construction of constraint-based models?

Global = Based on default primary projection planes Local or relative = based on object geometry. They are used as a way to reference object geometry

What leads are used in sketching? What style of lettering is used?

HB Soft Century Gothic

Distinguish the difference between height, width and depth auxiliaries

Height auxiliary view is projected from top view. Width from profile view. Depth from front view

Each object contains three dimensions. Identify them and the views in which each appears

Height, Width and Depth Frontal: Height and Width Profile: Height and Depth Top:Width and Depth

When a hidden line and center line coincide, which one should be shown? What are the rules for the precedence of lines?

Hidden Line Continuous line over hidden, hidden over center

What are the principal planes of projection or image planes? What is the role of these planes in orthographic projection?

Horizontal, Frontal, Profile They define the principle views: Top, Front, Right Side

What criteria should be used when selecting the front view?

Length and most details in front view

Radius

Line joining the center to any point on the circumference.

What are the different types of sweeps that can be performed within a 3D modeler? What is necessary to create a sweep?

Linear, circular, path based, blend Path and Profile

Primitive model

Models that are described using basic geometric forms.

Manifold Model

Models that unambiguously separate a region into the inside and outside. Solid models are restricted to manifold models.

What are the types of sketches and their use?

Multiview Pictorial

What are the other types of coordinate systems? What information is necessary to define points within each system?

Other systems include polar coordinates -used to locate points in any plane. They specify a distance and an angle from the origin. Cylindrical coordinates- involve one angle and two distances. Spherical coordinates involve two angles and one distance. World coordinate system- is reference system where geometry is defined and stored. It uses a set of three numbers located on 3 perpendicular axes and measured from origin. Local coordinate system- is a moving system that can be positioned anywhere in 3-D space by the user to assist in construction of geometry

????????????Using Figure 6.1 on page 298, describe the similarities and differences between perspective, oblique, axonometric, and multiview projection

Perspective projections are pictorial drawings used to represent 3-D forms on 2-D media. Such drawings create most realistic representations of objects. Oblique projection is parallel projection where projectors are perpendicular to each other but not perpendicular to projection plane. In oblique only front face is seen in its true shape. Axonometric projection is parallel projection technique used to create a pictorial drawing of an object by rotating the object on an axis relative to a projection.

What are standards and conventional practices as applied to technical graphics?

Sets of rules that govern how technical drawings are represented

What is a primary auxiliary view? Why do we use auxiliary views?

Single view projected from one of six principal views To see the true size and shape of a figure that would appear foreshortened in any of the principal views

Feature

Term used to describe physical portions of a part. Examples are hole, slot, stud, or surface.

What is the role of a production manager within the engineering design process

The person who has the ultimate responsibility for a design and its team

Unidirectional Associativity

The supporting application's data can be altered by changing the 3-D model but not vice versa. The supporting application's data can be altered by changing the 3-D model but not vice versa.

What is a drawing scale? How would you determine an appropriate drawing scale for a multiview drawing?

The traditional way to describe a scale (1:4) Size of the sheet of paper vs the size of the object

What are the different types of machined holes and how would you dimension them? Symbols?

Through, Blind, Counter bore, counter sink, spot face

What is necessary to define a linear or radial array/pattern? a mirrored feature?

Used in duplicating part features, linear array has a parent feature being copied in one or two dimensions with specifications given for distances between copies and total number of copies. Radial array, a axis of revolution is specified along with a radius, angular displacement, and total number of copies. In a mirrored feature, a mirror plane is specified along with features to be copied.

What is a working drawing? What is included in a complete set of working drawings?

Working drawings are complete set of standard drawings specifying the manufacture and assembly of a product based on its design. A complete set of working drawings includes detail drawings of each nonstandard part, an assembly drawing showing the standard and nonstandard parts in a single drawing, a bill of materials, and a title block.

Diameter

chord that passes through the center, twice the radius

What is the purpose of a sectional view?

clearly show internal part details

What is the difference between dimensional and geometric constraints?

dimensional = size geometric = shape

circumference

distance all the way around a circle

What are constraints? What is the difference between explicit and implicit constraints?

mathematical requirements placed on geometric models in a 3-D space. They differ in whether the modeling system infers the way the sketch was drawn or explicitly applies the constraint to the sketch

If you were going to layout an isometric pictorial drawing or sketch of an object that included inclined surfaces, how would you create the inclined surfaces? What is an isometric line? What is a non-isometric line?

plot the points

What rules should one follow when creating sketches?

proportions

What is concurrent engineering design? How is it different from a linear design process

the coordination of technical and nontechnical functions of design and manufacturing within a business. The people and processes are brought together at the very beginning which isn't normally done in the linear approach

What do hidden lines represent? When do we use section lines? cutting-plane lines? center lines? Which lines are thin? thick?

used for edges unseen from the current view. Used to see the inside of where a cutting plane goes through Used to indicate the location and direction of the section view shows the center of a circle All are thin except Short break, visible, cutting plane, and chain line