Isometric Projection - A Beginner's Guide

toe_head2001 · January 27, 2015

This tutorial is available as a PDF. Click here to view or download it

Introduction
Have you ever seen those cityscapes that have a strange (but awesome) angle to them? Like how Sim City 2000 or Age of Empires looked?

This is in Isometric Projection:

image via animatorkk.blogspot.com

Before we get started, let me stress that Isometric Projection is not the same as Pixel Art. The two are used together very often, but are separate things. Isometric Projection is about the angle of object; nothing more.

Examples:
Isometric Projection with Pixel Art - https://web.archive.org/web/20150506140101/http://cdn.whatanart.com/wp-content/uploads/2011/12/pixel-art-city-and-buildings.png
Isometric Projection without Pixel Art - https://web.archive.org/web/20150506140114/http://static02.mediaite.com/geekosystem/uploads/2013/04/stasisinfinite.jpg

Also, Isometric Projection is not limited to buildings, but for this guide, that's what we'll focus on.

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Isometric Projection vs Vanishing Points
Normally, objects will appear as if they are getting smaller with distance. This effect is usually achieved by using Vanish Points. You draw your first vertical line where ever you want, and then just extend the diagonal lines to the vanishing points. The rectangular prism below is in this perspective/projection. It is a parallelogram, but appears to slowly get smaller.

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With an Isometric Projection, all parts of the object are proportionally displayed; regardless of depth. It uses an angle of 30° for its diagonals. You just make sure that your diagonals are 30°, and the opposite ends are guaranteed to be equal lengths. Here is a different rectangular prism, but this one is in Isometric Projection. This time, you could pull out your ruler, and prove that it is a parallelogram if you wanted to.

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Drawing Your First Object
A note about the angles in paint.net:
paint.net can make a perfect 30° angle with the Line Tool, if the Shift key is press (look at the status bar for the angle). However, it measures the degrees in a counter-clockwise motion. If you start your line from the right and extend to the left, the angle should measure 150° (180° minus 30°).

It breaks down like this:
Bottom-Left to Top-Right: 30°
Top-Left to Bottom-Right: -30°
Bottom-Right to Top-Left: 150°
Top-Right to Bottom-Left: -150°

Another Note:
This next part of the guide is going to seem dead simple, but I suggest you read it all anyways. I've seen quite a few people do Isometric Projection incorrectly. If you try to do a complex building before mastering the basics, you'll get lost. Of course, for some people it just clicks; for everyone else, this part is for you...

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We'll make something simple -- an outline of a house. Remember, this is more of a beginner's guide or an introduction, and not so much of a step-by-step tutorial that you'd want to follow..... unless you want to make the same crude example.

Start with a vertical. For the purposes of this guide, the length won't matter.

Next up are the diagonals for the Front of the house. We'll make it an arbitrary length, but it practice you would probably want to measure to a specific length.

Close that up with a vertical line.

And we'll do the same thing for the side of the house, but not as long since it's the side.

Complete the ceiling...

For the actual roof, we'll first make some visual guides to assist us. You'll want to put these in their own layer, so you can trash them later.

Measure the length of the side of the house. This one happens to be 92px. We'll draw a line to the half way point... Here it would measure 46px. Do this on ends of the house.

Then draw a diagonal line from this point towards the opposite end of the house, making it as long as the previous line. Again, in this example it would be 46px. Do this on ends of the house.

At the ends of these lines, draw visual guides vertically. The length of these lines control the steepness of the roof, and can be what ever length you want. The longer the line is, the more steep the roof will be. I made this one 35px.

Now that you've got the guides, go ahead and connect the line for the apex of the roof. If you measured your guides correctly, this line will be 30° even without using the Shift key (use it anyways).

Connect the apex to the corners of the ceiling. We don't want the roof to end at the walls, so extend the lines past the wall a bit. NOTE: these are the only diagonal lines that are NOT 30°.
We wont' need those visual guides anymore...

Connect the ends of the roof.

In practice you wouldn't need to delete the ceiling lines, as roof shingles would cover all that up. But we'll do it here.

Getting more complex with your buildings
The rest is up to you!

Here's a example of a house I did a few weeks back.

And here it is with its roof cut away. You can see some of the guides for the roof and the windows.