Fundamentals of CAD MCQ Quiz - Objective Question with Answer for Fundamentals of CAD - Download Free PDF

Explanation:

.DWG:

• DWG is the proprietary file format used by AutoCAD to store 2D and 3D drawing data, including design data, metadata, and other information. This is the standard file extension for AutoCAD drawing files.

 Additional Information

.XML:

• XML files are used for storing structured data in a text format. This is not used for AutoCAD drawing files.

.PSD:

• PSD files are used by Adobe Photoshop to store raster images and layers. This is not associated with AutoCAD.

.DOC:

• DOC files are used by Microsoft Word for text documents. This is not related to AutoCAD drawing files.

Explanation:

Here, we got a little new type of question, so let's first understand the question itself.

• Control points term is generally used in the computer-aided geometric design system where these are a set of points used to determine the shape of a spline curve or, in more general terms, a surface or higher-dimensional object.
• In term B-spline curve designation "B" stands for Basis, so the full name of this approach to curve and surface design is the basis spline curve.

Now coming to the quadratic B-spline curve, we know that to design a quadratic curve in CAD we need to fix 4 control points.

• Two points need to be fixed at the endpoints of the curve section.
• But there can be an infinite number of curves passing through those two points by rotating the axis of the parabola.
• Then we need to fix two more points to arrest this rotation. Since the maxima need not lie in the centre of endpoints.

Hence finally we require 4 control points to generate a quadratic B-spline curve.

Understanding with a simple analogy,

Let's say someone asked "Number of minimum control points required to generate a straight line".

• Since we can draw a straight line through just one given point, and in question the minimum number of control points has been asked, so can we answer 1?
• No, absolutely no, since one point is not fixing the straight line, there can be still infinite many straight lines passing through the same point.
• So, we need to fix one more control point so as to fix the straight line.
• Hence there the minimum number of control points will be 2 for a straight line.

Similarly,

• With less than 4 control points, there will be infinitely many quadratic B-spline curves, passing through those points.
• With more than 4 control points, we cannot assure if there is at least one quadratic B-spline curve passing through those points.

Note:

If the question mentions the location of 1 particular control point at the maxima or minima point, then we need only 3 control points to generate a quadratic B-spline curve, but that is not the case here.

Explanation:

3-D Iconic models are Computer-Aided Design (CAD), specifically designed for

• Conveying real-world situations.
• To show the complete structure including the overhead structures.
• Also to easily explain the layout to management and stakeholders.
• 3D CAD models offer the stakeholders that common iconic representation base, where each of them can interpret the same product
  representation, and engage a discussion.

Explanation:

Drawing symbols of a surface:

Features	Tolerance Type	Characteristic	Symbol
For single features (not related to a datum)	Form	Cylindricity
		Flatness
		Profile of line
		Profile of a surface
		Roundness (Circularity)
		Straightness

Additional Information

Datum

• A datum is a theoretical exact plane, axis, or point referenced to a location that GD & T (Geometric Dimensioning and Tolerancing ) or dimensional tolerances.
• It can be considered as an anchor for the entire part, where the other features are referenced from.
• A datum feature is usually an important functional feature that needs to be controlled during measurement as well.
• All GD & T symbols except for the form tolerances like straightness, flatness, circularity, and cylindricity can use datums.
• When it comes to GD & T, datum symbols are your starting points where all other features are referenced from.

Features	Tolerance Type	Characteristic	Symbol
For single features (not related to a datum)	Orientation (Also called Attitude)	Angularity
		Parallelism
		Perpendicularity (Squareness)
		Profile of line
		Profile of a surface
	Location	Concentricity
		Coaxiality
		Profile of line
		Profile of a surface
		Position
		Symmetry
	Run-out (Also called composite)	Circular run-out
		Total run-out

Explanation:

Mapping:

• Mapping of a point (or a set of points) belonging to an object from one coordinate system to another is defined as changing the description of the point from the first coordinate system to the second one.
• Thus model position and orientation stay unaltered in space with respect to the origins of both coordinate systems while only the descriptions of such positions and orientations change as in the case of geometric models.

Translational Mapping:

• When the axes of two coordinate systems are parallel, the mapping is defined to be translational.
• The origins of both systems are different but their orientations in space are the same.

Rotational mapping:

• In this mapping system, both share the same origin and their orientation is different by an angle θ.

Explanation:

A grip point appears as blue colour when an object is selected. Using these, an object can be modified. A circle has 5 grip points. One in centre, 4 at each quadrant.

CAD (Computer Aided Design):

• CAD is the use of computers to aid in the creation, modification, analysis, or optimization of a design.
• A CAD drawing is a detailed 2D or 3D illustration displaying the components of an engineering or architectural project.
• CAD utilizes software to create drawings to be used throughout the entire process of a design project, from conceptual design to construction or assembly.
• DWG is the file format for AutoCAD, BricsCAD, IntelliCAD, Caddie, and Open Design Alliance compliant applications.
• DWG is a proprietary binary file format used for storing two- and three-dimensional design data and metadata.
• CAD software for mechanical design uses either vector-based graphics, or may also produce raster graphics showing the overall appearance of designed objects.
• CAD is used in many applications, including automotive, shipbuilding, and aerospace industries, industrial and architectural design, prosthetics, computer animation for special effects in movies, advertising, and technical manuals.

Explanation:

Here, we got a little new type of question, so let's first understand the question itself.

• Control points term is generally used in the computer-aided geometric design system where these are a set of points used to determine the shape of a spline curve or, in more general terms, a surface or higher-dimensional object.
• In term B-spline curve designation "B" stands for Basis, so the full name of this approach to curve and surface design is the basis spline curve.

Now coming to the quadratic B-spline curve, we know that to design a quadratic curve in CAD we need to fix 4 control points.

• Two points need to be fixed at the endpoints of the curve section.
• But there can be an infinite number of curves passing through those two points by rotating the axis of the parabola.
• Then we need to fix two more points to arrest this rotation. Since the maxima need not lie in the centre of endpoints.

Hence finally we require 4 control points to generate a quadratic B-spline curve.

Understanding with a simple analogy,

Let's say someone asked "Number of minimum control points required to generate a straight line".

• Since we can draw a straight line through just one given point, and in question the minimum number of control points has been asked, so can we answer 1?
• No, absolutely no, since one point is not fixing the straight line, there can be still infinite many straight lines passing through the same point.
• So, we need to fix one more control point so as to fix the straight line.
• Hence there the minimum number of control points will be 2 for a straight line.

Similarly,

• With less than 4 control points, there will be infinitely many quadratic B-spline curves, passing through those points.
• With more than 4 control points, we cannot assure if there is at least one quadratic B-spline curve passing through those points.

Note:

If the question mentions the location of 1 particular control point at the maxima or minima point, then we need only 3 control points to generate a quadratic B-spline curve, but that is not the case here.

Explanation:

The following command is used to draw geometry on AutoCAD.

Explanation:

Xrefs: Attaching and Detaching Referenced Drawings 

• You can attach any drawing file as an external reference or Xref in the current drawing.
• Attached Xrefs are links to the model space of a specified drawing file.
• Changes made to the referenced drawing are automatically reflected in the current drawing when it's opened or if the Xref is reloaded.
• The attached Xrefs do not significantly increase the size of your current drawing.

By using referenced drawings, one can

• Coordinate your work with the work of others by referencing other drawings in your drawing to keep up with the changes being made by other designers. You can also assemble a master drawing from component drawings that will change as a project develops.
• Ensure that the most recent version of the referenced drawing is displayed. When you open your drawing, each referenced drawing is automatically reloaded, so it reflects the latest state of the referenced drawing file.
• Keep the names of layers, dimensioning styles, text styles, and other named elements in your drawing separate from those in referenced drawings.
• Merge (bind) attached referenced drawings permanently with your current drawing when the project is complete and ready to be archived.

Important Points

An external reference can be a drawing file, image, PDF, or one of several other file types.

An Xref is an external reference that's specifically a DWG file.

Explanation:

The Various commands used in AutoCAD are:

Explanation:

Mechanism and shapes formation by cutting:

• The motion responsible for the cutting action is known as the primary motion or cutting motion.
• The motion responsible for gradual feeding the uncut portion is termed as the secondary motion or feed motion.
• The line generated by the cutting motion is called generatrix and the line generated from the feed motion is called the directrix.
• Various geometries can be obtained depending on the shapes of the generatrix and the directrix and their relative directions.

Generation of various surfaces:

Explanation:

Drawing symbols of a surface:

Features	Tolerance Type	Characteristic	Symbol
For single features (not related to a datum)	Form	Cylindricity
		Flatness
		Profile of line
		Profile of a surface
		Roundness (Circularity)
		Straightness

Additional Information

Datum

• A datum is a theoretical exact plane, axis, or point referenced to a location that GD & T (Geometric Dimensioning and Tolerancing ) or dimensional tolerances.
• It can be considered as an anchor for the entire part, where the other features are referenced from.
• A datum feature is usually an important functional feature that needs to be controlled during measurement as well.
• All GD & T symbols except for the form tolerances like straightness, flatness, circularity, and cylindricity can use datums.
• When it comes to GD & T, datum symbols are your starting points where all other features are referenced from.

Features	Tolerance Type	Characteristic	Symbol
For single features (not related to a datum)	Orientation (Also called Attitude)	Angularity
		Parallelism
		Perpendicularity (Squareness)
		Profile of line
		Profile of a surface
	Location	Concentricity
		Coaxiality
		Profile of line
		Profile of a surface
		Position
		Symmetry
	Run-out (Also called composite)	Circular run-out
		Total run-out

Explanation:

Central Processing Unit (CPU):​

• The CPU is the brain of a computer, containing all the circuitry needed to process input, store data, and output results.
• The CPU is constantly following instructions of computer programs that tell it which data to process and how to process it. Without a CPU, we could not run programs on a computer.
• The CPU can process those instructions easily, thanks to a control unit that knows how to interpret program instructions and an Arithmetic Logic Unit (ALU) that knows how to add numbers. With the control unit and ALU combined, the CPU can process much more complex programs than a simple calculator.
• CPU is also called the nerve center/brain of the system.
• At the hardware level, a CPU is an integrated circuit, also known as a chip. An integrated circuit "integrates" millions or billions of tiny electrical parts, arranging them into circuits and fitting them all into a compact box.

Additional InformationMonitor: monitors the display unit of the computer system.it display's the output of the system.

Storage devices:

• A storage unit is a part of the computer system which is employed to store the information and instructions to be processed. A storage device is an integral part of the computer hardware which stores information/data to process the result of any computational work.
• Without a storage device, a computer would not be able to run or even boot up. Or in other words, we can say that a storage device is a hardware that is used for storing, porting, or extracting data files.

Explanation:

Point-to-Point (PTP) Control System:

• When only the endpoint movement of a tool is important whereas the path followed by the tool in between endpoint movements is not important is called point to point control system.

• In the PTP control system, only one axis movement of a tool is sufficient.

          For Ex. Drilling, Reaming, Tapping, Boring Spot welding, punching, and blanking, etc.

Other types of Control System:

Straight-line Control System:

• In addition to the endpoint movement of a tool in the path followed by the tool is also important and if it is a straight-line path it is called a straight line Control system.
• Here 2- axes simultaneously movement is required.

• Ex. Straight turning, taper turning, shaping, planning, creating a straight Milling slot, etc.

​Contour Control System:

• In addition to the endpoint movement of the tool if a path followed by the tool is also important and if it is a contour path, it is called a contour control system.

          Here, 3 – axes simultaneous movement of the tool is required.

• But it is highly impossible to manufacture a perfect contour in the reality, whereas a contour is constructed by much linear distance travel of a tool between two consecutive points i.e. by Interpolation.