Create sketches, drawings, toleranced features, and parametric CAD models that other engineers can manufacture and inspect.
Course outline only for now. Full chapter-level lessons are still in progress. Use this page for readiness, concepts, worked-example format, practice, review, and portfolio direction. Complete course contents are live today for Math, Physics, and Statics.
01
Readiness check
Before starting, confirm the prerequisite habits.
Read basic orthographic views.
Understand scale versus true dimension.
Know size and location dimensions.
Recognize under-defined sketches.
0 or 1 weak itemContinue, but slow down at the worked example.
2 weak itemsReview the foundation page linked in the roadmap before solving practice problems.
3 or more weak itemsStep back to prerequisites; this module depends on them.
02
The core idea
Communicate a part unambiguously through views, dimensions, and constraints.
A drawing is an unambiguous contract: every feature needs a size and a location, and GD&T exists so that a fit means the same thing to the designer and the machinist.
feature = size + location
Works when: every feature carries both a size and a location dimension, and tolerances reflect function, not habit.
Breaks down when: you dimension to construction lines, leave a feature unconstrained, or stack tolerances so the fit becomes unbuildable.
Figure 1. Concept model for Engineering Graphics and CAD. The figure names inputs, computed variables, geometry, and result.
Figure 2. Worked problem setup: Prepare a drawing for an L-bracket with a 50 mm by 70 mm outline, 8 mm thickness, and a 12 mm mounting hole centered 25 mm from eaFigure 3. Calculation model. The result follows from the model, units, and reasonableness check.
Prepare a drawing for an L-bracket with a 50 mm by 70 mm outline, 8 mm thickness, and a 12 mm mounting hole centered 25 mm from each outside edge.
Problem Prepare a drawing for an L-bracket with a 50 mm by 70 mm outline, 8 mm thickness, and a 12 mm mounting hole centered 25 mm from each outside edge.
Given and find Outline 50 mm by 70 mm, thickness 8 mm, hole diameter 12 mm, hole center offsets 25 mm and 25 mm. Find: A minimum complete dimension scheme.
Assumptions Idealized model, consistent units, and no hidden effects outside the stated scope.
Step Show front view for the profile and one side view for thickness.
Step Dimension width, height, thickness, hole diameter, and hole center offsets.
Step Do not dimension the same feature twice.
Step Check that every feature can be made and inspected.
Conclusion 5 key dimensions. Carry this result into the design decision, not just into the answer box.
05
Misconceptions and diagnostics
Mistake
Symptom
Diagnostic question
Correction
Under-dimensioned feature
A hole has size but no location
Where is this feature measured from?
Give every feature a size and a location from a datum.
Tolerance stack-up
Chained dimensions accumulate error
Do these tolerances add along a chain?
Dimension from a common datum to avoid stack-up.
Over-tight tolerances
Specifies precision the function doesn't need
Does the fit actually require this?
Tolerance to function; loosen where you can.
06
Practice ladder
Level 1: direct skill
Redo the worked example with one changed input. Predict the trend before calculating.
Check yourself
The trend must match the governing relation: feature = size + location.
Level 2: mixed concept
Draw the model from memory, label knowns and unknowns, then write the first equation without looking.
Check yourself
Your first equation should connect the model to manufacturable print.
Level 3: independent problem
Create a similar problem from a real object near you. State assumptions, solve it, and include a reasonableness check.
Check yourself
A valid solution has a sketch, given/find list, governing relation, units, and a conclusion.
Level 4: transfer task
Turn the result into a design decision: what would you change if the output missed its target by 25 percent?
Check yourself
Name the design variable with the strongest influence and justify it from the equation.
07
Working with AI, and proving it yourself
Useful AI role
Ask for a critique of assumptions, units, diagram labels, and missing checks after you have attempted the solution.
Do not outsource
Do not paste the problem and accept a final answer. Your evidence is the model, the checks, and the explanation.
08
Retrieval and spaced review
Closed-notes prompts: pick a feature, give it a size and a location from a datum, choose a tolerance tied to its function, and state which datum you measured from.
TodayRedo the worked example from a blank page.
+1 daySolve Level 1 without notes.
+3 daysSolve Level 2 with changed numbers.
+7 daysConnect this module to another course.
+30 daysAdd a portfolio artifact.
09
Mapping and portfolio task
Course mapping
CAD and drawings are the language every other course speaks through: manufacturing reads your tolerances, FEM reads your geometry, and machine design is communicated as a dimensioned drawing.
First-pass focus: definitions, model setup, units, and worked examples. Save edge cases for the second pass.
Portfolio task
Create a one-page dimensioned drawing with a function-driven tolerance: sketch, assumptions, equations, result, reasonableness check, limitation, and recommendation.