GC 120 final exam

What is the standard angle of projection in the US?

3rd angle

detail drawing

A dimensioned, working drawing of a single part.

assembly drawing

A drawing that shows parts of an item when assembled.

drawing scale

A drawings relationship between a drawing size and the actual object

dimension line

A line that represents distance

extension line

A thin solid line perpendicular to a dimension line, indicating which feature is associated with the dimension.

What organizations develop standards and conventions applied to technical graphics?

ANSI and ISO

Major arc

An arc of a circle whose measure is greater than 180 degrees.

Primary auxiliary view

An auxiliary view that is developed directly from one of the normal views. ( 1 of 6)

parent-child relationship

Child feature is dependent on the existence of a parent feature

Assembly modeling

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

Whats the difference between dimensional and geometric constraints?

Dimensional= size Geometric= shape

views in which height, width, and depth appear

Frontal= height/width, Profile= Height/depth, Top= width/depth

What lead is used in sketching?

HB (soft)

What are the principle planes of projection or image planes?

Horizontal, Frontal, Profile; they define the principles views: top, front, right

precedence of lines

If multiple lines fall on top of each other, most important line is drawn. 1) Visible 2) Hidden 3) Center

Different types of sweeps

Linear, circular, path-based, blend

leader line

Lines that are thin and used to connect a specific note to a feature.

Constraints

Mathematical requirements placed on geometric models in a 3D space

What are the types of sketches?

Multiview and Pictorial

What style of lettering is used?

Single stroke gothic

Circumference

The distance around a circle

Radius

The distance from the center of a circle to any point on the circle

isometric drawing

The drawing of a 3d object that shows a corner view of a figure. it is not drawn in perspective and the distances are not distorted.

Whats the difference between explicit and implicit constraints?

They differ in whether the modeling system infers the way the sketch was drawn of explicitly applies the constraint to the sketch

Isometric Projection

Three dimensional drawing made up of equal angles of 120 degrees, most common 3-D drawing used in industry.

Different types of Boolean operations

Union, difference, intersection

working drawing

a drawing made to scale that shows the complete plans for an engineered product

Constructive Solid Geometry (CSG)

a method used to build solid models from primitive shapes based on Boolean set theory

mirrored feature

a mirror plane is specified along with features to be copied

Chord

a straight line connecting two points on a circle... can never be longer than the diameter

Conventions

accepted practices, rules, or methods

Minor arc

an arc that is smaller than a semicircle

Construction Geometry

any geometry created as part of the CAD modeling process that does not represent actual part geometry

Spherical coordinates

are used to locate points on a spherical surface by specifying two angles and one distance.

How are the axes related in a cartesian coordinate system?

axes are perpendicular to one another

Global Coordinate System (world)

based on default primary projection planes

local coordinate system (relative)

based on object geometry

Thin lines

center, long break, dimension, extension, section, hatch, stitch, phantom, hidden, symmetry

Bidirectional associativity

changes in either the 3-D model or data in the supporting application will affect the other

Cartesian coordinate system

commonly used in mathematics and graphics, locates the positions of geometric forms in 2-D and 3-D space

Solid Model

consists of volumetric information, what is on the inside of the 3-D model, as well as information about the surface of an object

Mitre line

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

constraint-based model

creates a dynamic model by having the model defined by a series of modifiable features

What types of lines are associated with section views?

cutting plane lines, section lines, centerlines, object lines

What are the different methods for defining a sweep distance?

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

What are different types of section views?

full, partial, half, revolved, removed

Whats the difference between height depth and width auxiliaries?

height from the top, depth from the front, width from the profile

Cylindrical coordinates

involve one angle and two distances

What criteria should be used when selecting the front view?

length and most details in front view

Primitive model

models that are described using basic geometry

Manifold Model

models that unambiguously define a boundary between the inside and outside of an object.

Local coordinates

moving system that can be position anywhere in 3-D space to assist in construction of geometry

Concurrent engineering design

nonlinear team approach; brings together input, processes, and output necessary to produce a product

1st angle projection

observer-object-projection plane

3rd Angle Projection

observer-projection plane-object

What is necessary to create a sweep?

path and profile

How would you create inclined surfaces?

plot the points

What rules should one follow when creating sketches?

proportions

World coordinates

reference system where geometry is defined and stored. uses a set of three number located on 3 perpendicular axes and measured from the origin

convergent projection

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 the multiple points on an imaginary line parallel to the object

Standards

sets of rules that govern how technical drawings are represented

Thick lines

short break, visible, cutting plane, chain, symmetry

linear array

specifications given for distances between copies and total number of copies

radial array

specified along with a radius, angular displacement, and total number of copies

Contour Dimensioning

the contours or shapes of the object are dimensioned in their most descriptive view

Diameter

the distance across a circle through its center (2r)

degrees of freedom

the strength of a relationship between components. Les degree means more established geometric relationship

Unidirectional associativity

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

What are the different types of machined holes?

through, blind, counter bore, counter sink, spot face

What is purpose of a section view?

to clearly show internal part details

Why do we use auxiliary views?

to see the true shape of a figure that would appear foreshortened in principle views

Cutting plane lines

used in section drawings to show the locations of cutting planes

Section lines

used in section views to represent surfaces of an object cut by a cutting plane

Polar coordinates

used to locate any points on a plane, it specifies a distance and an angle from the origin.

Hidden lines

used to represent features that cannot be seen in the current view

Center lines

used to represent symmetry and paths of motion and to mark the centers of circles and the axes of symmetrical parts, such as cylinders and bolts