CAD/CAM MCQ Quiz - Objective Question with Answer for CAD/CAM - Download Free PDF

Explanation:

• The .max file extension is the native file format for 3ds Max, which stores all the information about the scene, including:

  • Geometry

  • Lighting

  • Materials

  • Animations

  • Camera settings

• It is the primary format for saving scenes and supports the complete project configuration.

• Unlike .3ds, which is used for older 3D Studio versions, .max is fully optimized for 3ds Max.

• Other formats like .obj and .fbx are mainly used for exporting models to other software but do not store complete scene information.

Explanation:

• The Modifier Stack in 3ds Max allows you to:

  • Apply multiple modifiers to an object (e.g., Bend, Twist, TurboSmooth).

  • Control the order of application for different modifiers.

  • Toggle visibility, enable or disable modifiers.

  • Non-destructive modeling: Modifiers can be added or removed without altering the base geometry.

Explanation:

• The Render Setup dialog controls:

  • Output resolution and image size

  • Frame range for animations

  • Render quality settings like anti-aliasing, global illumination, and shadows

  • File format for rendered outputs (JPEG, PNG, AVI, etc.)

• This is the final step before outputting an image or animation.

Explanation:

• The Schematic View is accessed through the Graph Editors menu.

• It provides a visual representation of object relationships and hierarchies:

  • Shows parent-child links

  • Displays modifiers, controllers, and animation paths

  • Allows drag-and-drop linking of objects

• It is particularly useful for rigging and managing complex animations.

Explanation:

• In 3ds Max, the Undo command is used to revert the last action.

• Shortcut for Undo is Ctrl + Z.

• This command can be performed multiple times to backtrack through recent changes.

• The opposite operation, Redo, is performed with Ctrl + Y.

Explanation:

Section:

• Sectional views are drawn to show the internal details of an object.
• The object is assumed to be cut on a plane.
• The surface produced by cutting an object at this plane is called a section.
• The surface which cuts the object at the section plane is shown hatched (a regular pattern) according to standard conventions.
• Sections are of many types:
  1. Full section
  2. Offset section
  3. Half section
  4. Revolved section
  5. Removed section
  6. Partial section, or broken section
  7. Auxillary section
  8. Aligned section. 
• The type of section to be adopted depends upon the shape of the object.

Half section:

• This is generally used for symmetrical objects.
• Two cutting planes at right angles to each other pass halfway through the view up to the centerline.
• Thus only one quarter is assumed to be removed.

Additional Information

Revolved section:

• It is used to show the cross-section shape of ribs, arms, spoke, etc. The section line is drawn by passing a cutting plane at right angles to the axis.
• This section is then revolved and drawn at the cutting plane axis on the main view. If the cross-section changes along the length, many revolved sections can be drawn.  
• ​​When the sectional view is shown within the object it is known as a Revolved section.

 

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Removed section:

• It is similar to Revolved section, but instead of drawing the section on the view, it is drawn in a free space near the object along the centerline of the section.

 

Partial section:

• A section consisting of less than half a section is called a partial section. Note that here we use a broken line to indicate the division between the sectioned and unsectioned part. For this reason, a partial section is often called a Broken section.

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Aligned section:

• An aligned section view/cut is a view created from a cutting profile defined from non-parallel planes. In order to include in a section a certain angled element, the cutting plane may be bent so as to pass through those features. The plane and feature are then imagined to be revolved into the original plane.

Full section:

• The cutting plane passes entirely through the object in a straight line. Thin objects like ribs, etc. are not hatched even if they are cut by the cutting plane along the axis.
• To see the internal features of an object that are not in a straight line, the cutting plane can be offset. Such a section is called the Offset section. The cutting plane can be inclined also.

Mainframe is a very large in size and expensive computer capable of supporting thousands of users simultaneously. Mainframe executes many programs concurrently.

Minicomputer is a midsize computer. A minicomputer is a multi-processing system capable of supporting up to 250 users simultaneously. A minicomputer is a computer of a size intermediate between a microcomputer and a mainframe.

A microcomputer is a complete computer on a smaller scale and is generally a synonym for, personal computer or PC, a computer designed for an individual.

Workstation is a computer used for engineering applications such as Computer Aided Design/Computer Aided Manufacturing (CAD/CAM), desktop publishing, software development, and other types of applications, which require a moderate amount of computing power and relatively high quality graphics capabilities.

CAD is the use of computer technology for design and design documentation. CAD/CAM applications are used to both design a product and program manufacturing processes, specifically, CNC machining. CAM software uses the models and assemblies created in CAD software to generate tool paths that drive the machines that turn the designs into physical parts.

Explanation:

Open-loop control system:

The open-loop control system can be described by a block diagram as shown in the figure below.

These are the systems in which the control action is independent of output.

Ex: Traffic signals, washing machine and bread toaster, systems having no sensor, etc.

Advantages:

• Simple construction and design
• Cost is less
• Maintenance is easy
• No problem with instability
• Convenient to measure when the output is difficult to measure

Disadvantages:

• These are less accurate, and their accuracy depends on the calibration.
• Inaccurate results are obtained with parameter variations within the system.
• Recalibration of the controller is required from time to time to maintain accuracy. 

Stepper Motor: 

• A stepper motor is a pulse-driven motor that changes the angular position of the rotor in steps.
• Due to this nature of a stepper motor, it is widely used in low cost, open-loop position control systems.
• A stepper motor can also be controlled in this full servo closed-loop mode with the addition of an encoder.

​Additional Information

Servomotors 

• Servomotors are special electromechanical devices that produce precise degrees of rotation. 
• Servomotors are also called control motors as they are involved in controlling a mechanical system. The servomotors are used in a closed-loop servo system. 
• A feed drive consists of a feed servomotor and an electronic controller. 
• The feed motor has certain special characteristics, like constant torque and positioning which are done by servo-motors.

Synchronous Motors: In the synchronous motor the stator poles are wound with coils and the rotor is a permanent magnet and is supplied with current to create fixed polarity poles.

Induction Motor: In the case of an induction motor, the stator is similar to the synchronous motor with windings but the rotors’ construction is different. 

Brushless DC motor (BLDC motor):

• A BLDC motor is an electronically commuted DC motor which does not have brushes.
• A typical brushless motor has permanent magnets that rotate around a fixed armature.
• Brushless DC (BLDC) motors are well-suited for servo applications due to their high efficiency and reliability, low rotor torque (which improves dynamic response), and linear speed-torque relationship.

Closed-loop control system:

The open-loop control system can be described by a block diagram as shown in the figure below.

These are the systems in which the control action depends on the output. These systems have a tendency to oscillate.

Ex: Temperature controllers, speed control of the motor, systems having sensors, etc.

Advantages:

• More accurate
• Non-linear distortions are less
• The output is less sensitive to parameter changes within the system
• Bandwidth increases

Disadvantages:

• Design is complicated
• More expensive
• May become unstable, if there are malfunctions in the feedback.

The field controlled system is an open-loop control system.

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.

Concept:

AutoCAD is a commercial computer-aided design (CAD) and drafting software application. Developed and marketed by Autodesk

AutoCAD was first released in December 1982 as a desktop app running on microcomputers with internal graphics controllers.

Before AutoCAD was introduced, most commercial CAD programs ran on mainframe computers or minicomputers, with each CAD operator (user) working at a separate graphics terminal. 

Since 2010, AutoCAD was released as a mobile- and web app as well, marketed as AutoCAD 360.

Explanation:

INTERFERE

• This command can be used to detect intersecting 3D solids.
• The command is especially useful in situations where you want to detect clashes between different solids like pipes and walls.
• The INTERFERE Command checks to see whether 3D solids intersect, and it's similar to the INTERSECT command with a few differences.
• By default, the INTERSECT command deletes the original objects, whereas the INTERFERE command retains the original objects and creates a new 3D object in the location where the 3D solids intersect.

INTERSECT

• The INTERSECT command keeps the shared areas of two solids that are used to sculpt and alter the shape of a 3D solid to create new contours or features.

Explanation:

The following command is used to draw geometry on AutoCAD.

Command	Comment
XLINE	For Infinite line
OFFSET	Offset an object by distance (parallel)
INTERSECT	For Intersecting lines
ARC	For arc with 3 points
CIRCLE	Draw a circle
FILLET	Draw an arc between 2 intersecting lines
LINE	Draw a line (for perpendicular also)
EXTRUDE	To create 3D solid
TRIM	To trim the object
REC	For drawing rectangle
EXTEND	Boundry object selection

Explanation:

AUTOCAD is a commercial Computer-Aided Design software application.

Uses of AUTOCAD:

1. Easy to design in 3D & 2D.

2. Easy to understand as available in many languages.

3. AUTOCAD supports a number of Application Programming Interference for customization and automation.

Command and shortcut for drawing geometrical diagram:

Command Name	Shortcut Key
Rectangle or Square	REC Enter
Line	L Enter
Circle	C Enter
Ellipse	EL Enter
Polygon	POL Enter