What are the three main orthographic views?

Front, top (the plan view) and right side. The front view is chosen as the most descriptive face, and the others are projected from it.

What is the difference between first-angle and third-angle projection?

They are two conventions for arranging the views. Third-angle, used in the US, places each view on the side you look from. First-angle, common in Europe, places it on the opposite side. A small symbol in the title block says which one is used.

Why use orthographic views instead of a 3D picture?

A 3D picture has perspective, so you cannot measure off it reliably. Orthographic views are to scale and undistorted, so every dimension can be read and trusted.

How many views does a drawing need?

As few as describe the part without ambiguity — often two or three. A simple flat part may need only one view plus a thickness note.

What are orthographic views in a technical drawing?

Looking at each face dead-on

Orthographic views are the flat, straight-on views of a part. Each one is drawn as if your eye were directly in front of a single face, looking at it square, with no perspective — parallel lines stay parallel and nothing tapers off into the distance. The word orthographic literally means “drawn at right angles.”

That lack of perspective is the whole point. Because each view is to scale and undistorted, you can put a ruler on it and the numbers are real. A 3D picture or render cannot do that: perspective shortens the far edges, so any measurement you take off it is wrong.

The front, top and side

A part is usually described with two or three views, projected from one another so they line up:

Front view — the most descriptive face, chosen as the main view everything else is built around.
Top view (plan) — what you see looking straight down, lined up directly above the front view.
Side view — usually the right side, lined up beside the front view to show depth.

Read together, these flat views reconstruct the full 3D shape in your head, which is why a drawing can fully define a part without ever showing it in 3D.

First-angle vs third-angle projection

There are two conventions for where each view is placed on the sheet:

Third-angle (standard in the US and Canada) puts each view on the same side as the face you are looking from — the top view goes above the front view.
First-angle (common in Europe and much of the world) puts each view on the opposite side — the top view goes below the front view.

Mixing them up flips the part, so drawings carry a small projection symbol (a truncated cone) in the title block to say which one is used. Always check it before you read the layout.

Orthographic views trade the “realism” of a 3D picture for something far more useful in a workshop: views you can measure. That is the trade every technical drawing makes.

Getting clean views of your own part

You do not need to set up projection by hand. TechDraw AI takes a photo of your part and produces clean, to-scale views with dimensions, so you get a measurable drawing instead of a perspective photo. For the full picture of what a finished sheet contains, see what is a technical drawing, and for sending it on, how to make a drawing for CNC machining.