← All Modules
02 Blueprints

Reading Drawings I - Views & Dimensions

Learn to read the three standard flat views (front, top, and side — called orthographic views) and the dimensions that engineers use to define a part before you model it.

Beginner ~10 min

Orthographic Views

Before you can build a 3D part, you have to read the flat views that engineers use to share ideas. Every drawing shows your part from a few sides at once.

The Three Main Views
Front View

The most important face. Usually shows the biggest or most detailed side of the part.

Top View

Drawn directly above the front view. Shows the part from above.

Right Side View

Drawn directly to the right of the front view. Shows depth.

1 Experience
2 Reflect
3 Theorize
4 Apply
Two Drawing Standards
  • ASME (North America): Third-angle projection. Top view goes above Front. Dimensions in inches.
  • ISO (rest of the world): First-angle projection. Top view goes below Front. Dimensions in millimeters.

Always check the title block (bottom right of the drawing) to see which standard and units are being used.

Dimensions & Symbols

Every dimension on a drawing tells you exactly how big a feature should be.

Symbols You Will See
  • ⌀ (diameter): The distance across a full circle - used for holes and shafts.
  • R (radius): The distance from the center of an arc to its edge - used for fillets and rounds.
  • ± (plus/minus): Tolerance - how much the real part is allowed to vary from the number shown.
  • ∇ (depth): How deep a hole or pocket goes into the part.
How to Read a Drawing in Order
1
Find the Front View

It usually shows the most defining features. Top and Right align with it.

2
Grab the Big Dimensions

Length, width, and height - the bounding box of the part.

3
Find the Feature Dimensions

Hole diameters, fillet radii, pocket depths - every detail that drives CAD.

4
Check the Title Block

Material, scale, default tolerance, and units live here.

Tip: Dashed lines on a view are hidden edges - features that exist but can't be seen from that angle. Solid lines are visible edges.
Pause and Reflect
✓ Your reflections are saved automatically
Apply What You Learned

Grab any printable drawing (from a toy, a kit, or online) and decode it.

  • Identify the Front, Top, and Right views
  • Extract the three overall dimensions (Length, Width, Height)
  • Find every hole and write down its diameter
  • Read the title block for material and default tolerance
  • Spot any dashed (hidden) edges and explain what feature they show
0 / 5
← Previous
Next →