Home / Articles / First-angle vs third-angle projection: reading and drawing views correctly
Basics · Technical drawing

First-angle vs third-angle projection: reading and drawing views correctly

7 min read · updated 30 Oct 2026

Most mechanical drawings use several orthographic views — front, top and side. What differs is how the views are arranged, and there are two systems: first-angle projection, common in Europe and wherever ISO standards are followed, and third-angle projection, used in the United States and Japan. Read a drawing in the wrong system and a hole or step on the left gets made on the right, so every drawing must state its system with a symbol in the title block.

Where each view goes

First angle Front Side(from left) Top Third angle Top Front Side(from right)
First angle: the top view goes below the front view, and the view from the left goes on the right. Third angle: the top view goes above, and the view from the right goes on the right. The projection symbol for each system is shown underneath.
First angleThird angle
Top viewBelow the front viewAbove the front view
View from the leftTo the right of the front viewTo the left of the front view
View from the rightTo the left of the front viewTo the right of the front view
IdeaThe object sits between you and the projection plane, so each view lands on the far sideThe projection plane sits between you and the object, so each view lands on the side you look from
Common inEurope, China, ISO-based workUSA, Japan

A simple way to remember third angle: "the view goes on the side you look from". First angle is the opposite. Many countries and companies use both depending on the customer, so always check the symbol rather than guessing.

The truncated-cone symbol

The symbol defined in ISO 5456-2 shows a truncated cone twice: once from the side (a trapezoid) and once from the small end (two concentric circles). Look at which end of the trapezoid faces the circles:

  • First angle: the wide end of the trapezoid is next to the circles (the narrow end points away).
  • Third angle: the narrow end of the trapezoid is next to the circles (it points towards them).

Some drawings put the circles on the left and some on the right, so left or right is not what decides it — which end of the cone is nearest the circles is. The symbol usually sits in the title block in the bottom-right corner. If a drawing has none, ask the designer before anything is made.

Drawing the views in DXCAD2D Online

  1. Open DXCAD2D Online and draw the front view first — it shows the most about the shape.
  2. Turn on object snap (F3), Ortho (F8) and tracking (F11). Hover over a corner or edge of the front view until a + appears, then draw along that line, so the edges of the top and side views line up exactly with the front view.
  3. Place the top and side views according to your system, as in the table above. Draw hidden edges as dashed lines on their own layer.
  4. Dimension with D, then choose Export → PDF…, tick the drawing frame option and set the projection symbol to first or third angle to match what you drew.

Try it right now — a free 2D CAD in your browser. Nothing to install, no sign-up.

Open DXCAD2D Online

Things to watch when issuing drawings

  • Use one system for the whole drawing set; never mix first and third angle in one set.
  • Any view not in a standard position (an auxiliary view, say) needs an arrow and a letter, such as "View A".
  • The isometric view is there to help understanding; do not put manufacturing dimensions on it.
  • Check that the symbol in the title block matches the actual arrangement, especially when reusing an old template.

For dimensioning, read ISO dimensioning basics; for paper and frames, see drawing paper sizes.

Related articles