Deck 2: Wireframe and Surface Modeling in AutoCad

Question 1

To avoid surprises when you create a wireframe model, it is a good idea to

A)avoid using object snaps.
B)stay in the default world coordinate system.
C)specify coordinates using the absolute technique.
D)view the model from the top (plan) view while working.

Answer 1

specify coordinates using the absolute technique.

Question 2

Compared with surface and solid models, wireframe models take

A)about the same amount of time to create.
B)less time to create.
C)more time to create.
D)about 30 minutes to create.

Answer 2

about the same amount of time to create.

Question 3

Surface models are considered to be more advanced than wireframe models because

A)they can be used to calculate mass properties.
B)they have surfaces (faces).
C)they have volume.
D)they can be used to calculate holding properties and weights.

Answer 3

they have surfaces (faces).

Question 4

An analytic surface is one that

A)is described by an equation or set of equations.
B)is formed from a set of data points that are used as control points.
C)interpolates the input data, allowing control of individual data points.
D)is created using a minimum of four curves that have adjoining edges.

Question 5

Surface models are used mostly in

A)modeling mechanical parts.
B)creating architectural models.
C)modeling complex electrical systems.
D)modeling complex curves in boat hulls and car fenders.

Question 6

The number of segments in a tabulated surface is controlled by the

A)SURFTAB1 system variable.
B)SURFTAB2 system variable.
C)SURFTYPE system variable.
D)EDGESURF command.

Question 7

A fillet surface is used to

A)reshape a bicubic Coons patch with smooth curves.
B)round the edges of a planar surface.
C)blend two surfaces together.
D)convert facets into smooth curves.

Question 8

A surface primitive is a(n)

A)basic 3D object that can be used to create more advanced models.
B)wireframe model from which surface models can be created.
C)2D object that can be extruded to form a surface model.
D)analytic surface from which nonanalytic surfaces can be created.

Question 9

All of the following are surface primitives except the

A)box.
B)cone.
C)spiral.
D)dish.

Question 10

To create an approximation of a Coons patch in AutoCAD, use the

A)3DMESH command.
B)REVSURF command.
C)TABSURF comman
D)EDGESURF command.

Question 11

The Spline option of the PEDIT command

A)creates an arc-fit polyline joining each pair of vertices to convert a straight-line polyline into a curve.
B)uses the vertices of the polyline as control points to create a curve approximating a B-spline.
C)generates the linetype in a continuous pattern through the vertices of the polyline.
D)smoothes a polygon mesh surface.

Question 12

To control the type of surface created using the Smooth surface option of the PEDIT command, use the

A)SURFTAB1 system variable.
B)SURFTAB2 system variable.
C)SURFTYPE system variable.
D)EDGESURF command.

Question 13

Solid models are used more frequently than surface models or wireframes because they

A)result in smaller files.
B)are more accurate.
C)can be viewed from any point in 3D space.
D)allow you to calculate mass properties.

Question 14

The disadvantage of solids created using pure primitive instancing is that

A)they are less accurate than solids created using cell decomposition.
B)they must be converted to another type of solid before they can be edited.
C)they are created using the B-rep format.
D)some of the parameters of the solids are not specified.

Question 15

By default, AutoCAD displays all kinds of models in wireframe format. To find out which type of solid a specific model is, use the

A)ID command.
B)REGEN command.
C)LIST comman
D)MODELTYPE system variable.

Question 16

Spatial occupancy enumeration is rarely used in CAD applications because it

A)requires a large amount of memory.
B)is not sufficiently accurate for CAD work.
C)requires an obscure operating system.
D)does not allow 3D solids to be edited.

Question 17

To store and display modeling information, AutoCAD uses

A)cell decomposition.
B)boundary representations and sweeping.
C)constructive solid geometry.
D)pure primitive instancing.

Question 18

All of the following are examples of solid primitives except the

A)sphere.
B)cone.
C)dome.
D)pyramid.

Question 19

The ISOLINES system variable specifies

A)the number of segments in a tabulated model.
B)the number of contour lines that define a solid model.
C)the direction of contour lines in a solid model.
D)the length of the segments in an extrusion.

Question 20

All of the following objects can be extruded except a(n)

A)arc.
B)polyline.
C)ellipse.
D)region.

Question 21

To create a revolved solid, use the

A)EDGESURF command.
B)REVSURF command.
C)REVOLVE command.
D)EXTRUDE command.