CAD CAD Specialist Mechanical Design and Engineering 1 — Questions and Answers
Question 1: In mechanical CAD, what does GD&T stand for?
- General Design and Tolerance
- Geometric Dimensioning and Tolerancing (Correct answer)
- Graded Drawing and Toolpath
- Geometric Drawing and Tracking
Correct answer: Geometric Dimensioning and Tolerancing
GD&T (Geometric Dimensioning and Tolerancing) is a symbolic language used on engineering drawings to define the allowable variation in form, orientation, and location of features.
Question 2: What is the purpose of a 'datum' in GD&T?
- A tolerance zone applied to a surface
- A theoretically exact reference point, axis, or plane from which measurements are made (Correct answer)
- A type of weld symbol on a drawing
- A layer convention for mechanical drawings
Correct answer: A theoretically exact reference point, axis, or plane from which measurements are made
A datum is a theoretically exact reference feature (point, axis, or plane) used as the origin from which geometric tolerances and dimensions are measured.
Question 3: In Inventor or SolidWorks, what is a 'parametric model'?
- A model generated from a spreadsheet formula
- A model whose geometry is driven by editable dimension parameters (Correct answer)
- A model imported from a neutral file format
- A model with predefined material properties
Correct answer: A model whose geometry is driven by editable dimension parameters
A parametric model stores design intent through dimensions and constraints, so changing a parameter automatically updates the entire model geometry.
Question 4: What is a 'bill of materials' (BOM) in mechanical CAD assembly design?
- A cost estimate for raw materials
- A structured list of all components, quantities, and part numbers in an assembly (Correct answer)
- A toolpath report for CNC machining
- A layer list used in the assembly drawing
Correct answer: A structured list of all components, quantities, and part numbers in an assembly
A BOM (Bill of Materials) is a structured table listing every part, sub-assembly, quantity, and part number that makes up a product assembly.
Question 5: In mechanical drafting, what does a 'section view' show?
- An external isometric view of the part
- The interior features of a part as if it were cut open along a cutting plane (Correct answer)
- A detail view magnifying a small feature
- A view showing hidden lines in dashed format
Correct answer: The interior features of a part as if it were cut open along a cutting plane
A section view exposes the internal features of a part by showing it as if it were cut along a defined cutting plane, revealing interior geometry.
Question 6: What is the function of 'mating constraints' or 'mates' in a CAD assembly?
- Assigning material properties to components
- Defining geometric relationships that position and constrain parts relative to each other (Correct answer)
- Creating exploded view animations
- Applying GD&T symbols to assembly drawings
Correct answer: Defining geometric relationships that position and constrain parts relative to each other
Mates (or assembly constraints) define how parts relate to one another — coincident, concentric, flush, etc. — to correctly position components in an assembly.
CAD CAD Specialist Mechanical Design and Engineering 1
In mechanical CAD, what does GD&T stand for?