How games work, from the ground up

Why does a character run faster diagonally? Why does a fair 25% chance feel unfair? What makes a wet stone look wet? Short lessons with demos you can play with, one idea at a time. No math or programming needed to start.

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Who it's for

1. Color is numbers
2. Normals and light
3. UV
4. Shader
5. Surface properties
You're starting from zero
Courses take you through in order, and each idea is explained before you need it. You don't need school math or programming.
Browse the courses
Without the theory
Make the rock look nicer
With the theory
The rock looks like plastic — raise the roughness to 0.8
You're making a game with AI
While the assistant writes the code, you learn what's going on underneath — enough to give it sharper tasks and catch its mistakes.
See what's inside
- Cheat sheetTexture settings for every map
- FlowA master material from scratch
- ReferenceUnreal material nodes
You already work in games
Cheat sheets, common pitfalls and search across every lesson: look something up and get back to work.
All cheat sheets

Where do you want to start?

A course is a set of lessons on one subject, in order. Each lesson goes in small steps: read a bit, answer a question, move on.

Start here

First steps in game development8 lessons

Graphics

Art and worlds

Code and math

Design and release

Open the courses

Sound familiar?

The lessons explain why it happens, not just which button to press.

The bumps on your rock look dented in
The normal map's green channel is flipped: Blender writes it one way, Unreal reads it the other.
Explained in the lesson “Normals and light”
A bullet flies straight through a wall
Physics sees the world in snapshots, and a fast object can skip over the wall between two of them.
Explained in the lesson “Why fast bodies fall through walls”
The camera lurches when it starts to move
Simple smoothing sets off at full speed. A spring keeps track of its speed and eases in.
Explained in the lesson “Springs and damping”

Demos you can play with

These are the real demos from the lessons, not screenshots. Change the numbers, drag things around and watch what happens.

Try it

Move the sun. On the left is a cross-section of a rock, on the right a sphere. Then turn on the normal map.

Sun−35°

normal map show the normal map as color

Cross-section of a rock: the blue arrows are normals, and the numbers are the brightness of each face.

sphere without a normal map

From the lesson “Normals and light”

Try it

The weight is pulled 20 cm down and let go. On the right you see its position over time, and the pale line shows the same spring with critical damping. Change the stiffness and the mass, and watch the period. Then pick a damping mode with the buttons, or move the damping slider yourself. Notice that with a heavier weight, the same damping setting lets it swing.

Stiffness100 N/m Mass1.0 kg Damping4 N·s/m

From the lesson “Springs and damping: a smooth camera and soft motion”

Try it

On the left is the heightmap of a 32 × 32 meter plot, on the right the ground the engine builds from it. The plot has a path 1 meter wide and a boulder about 2.5 meters wide. Change the grid step and see what is left of the path and the boulder. With a coarse step the path turns into a wide shallow dip, and the boulder into a gentle bump. Click the map to see which vertex stands on that pixel and how high it is.

show the grid

Heightmap: a pixel is a vertex

The ground built from this map

From the lesson “Landscape: terrain from a heightmap”

Try it

Drag the shapes by their centers. When they touch, they turn red, and the arrow shows the normal and the depth: which way and how far to push B out. In “axis-aligned boxes” mode, the shadows lie at the bottom and on the left, and the boxes touch only when both pairs of shadows overlap. In “rotated boxes” mode, turn the boxes with the sliders. The drawing shows the axis the test picked: one with a gap, if there is one, and otherwise the one with the smallest overlap.

Rotation of A20° Rotation of B55°

From the lesson “Collisions: how the engine knows that objects touch”

What a lesson looks like

Part of a real lesson. It starts with something from everyday life, then gets to the mechanism and the formula, with a question after each part.

Terms are explained on the spotHover over a dotted word. The academy has 3406 terms, and each one has a lesson that explains it.
Formulas come in words firstFirst what it's made of and why it looks that way. The letters and symbols come later.
Every answer gets an explanationPick any option and the lesson tells you why it's right or wrong. There are 3627 questions across the academy.

LessonNormals and light

Why the face toward the sun is brighter

Take a flashlight and a sheet of paper. Shine the light straight at the sheet, and the spot is bright. Tilt the sheet, and the same beam spreads over a larger area, so each square centimeter gets less light. Turn the sheet edge-on, and the light slides along it and does not land at all.

How bright a surface is depends on the angle between the normal and the direction to the light: an arrow from the surface toward the sun or a lamp. The cosine of that angle tells you how quickly the surface darkens as the angle grows. The cosine is a number that falls from 1 to 0 as the angle goes from 0° to 90° (the lesson “Angles, sine and cosine” shows where it comes from). Brightness is proportional to the cosine, and this is Lambert’s cosine law. The cosine of 0° is 1 (light head-on), the cosine of 60° is 0.5, and the cosine of 90° is 0 (light grazing the surface).

A shader computes the cosine with the dot product. It takes two arrows and gives back one number: multiply their matching coordinates and add the results (the box below shows how). For two arrows of length 1, that number is the cosine of the angle between them.

brightness = max(0, dot(normal, direction to the sun))
color      = BaseColor × sun color × brightness      // the multiplication from lesson 1

A question from the lesson

The sun is straight overhead, and a face is vertical, like a wall. How bright is it?

Read the whole lesson

What's inside

The same lessons, plus reference pages, sorted by subject — for when you need to look one thing up.

31courses
16sections
502pages
3,406terms
3,627questions

Graphics

BasicsSpaceTexturesMaterialsSurface physicsLightThe frameUnder the hood

Math and physics

VectorsAngles and rotationsTransitions, randomness, numbersGeometryChange and wavesPhysics of motionPhysics of bodiesVehiclesCheat sheet

Tech art

Shaders by handShader techniquesProcedural generationTools and pipelineOptimization

Art

Art fundamentalsStyle and conceptModelingZBrushUnwrapping, baking, exportTexturingSubstance PainterSubstance DesignerCharacters2D graphics

Environment

NatureArchitectureThe scene

World and levels

The ideaLevel designSpace and combatTerrainWater and roadsVegetation and placementLarge worldsWorld breakdownsLevel breakdowns

Effects

BasicsNiagara in depthWorld and combat effectsThe cost of effects

Animation

Basics of motionSkeleton and rigAnimation in the engineFaces and motion captureCamera and cutscenes

Game design

BasicsMechanics and systemsProgression and economyStoryPracticeGame breakdowns

Interface and UX

InterfaceUXInterface in Unreal

Programming

How a game worksFrom scratchBlueprintsC++ in UnrealThe game frameworkPatterns and architectureSpeed and memoryUnreal pitfalls

Character AI

BasicsMovementDecisions and perceptionBreakdowns

Multiplayer

BasicsSynchronizationServicesBreakdowns

Sound

BasicsSound designSound in the worldToolsMusic and voice

Production and release

How a game gets madeTeam toolsTestingBuilds and platformsStores and releaseMarketingMoney and lawCareer

Reference

ProgressReviewAll pages by typeToolsResources

Questions come back before you forget

Answer a question and it comes back a day later, then after 3, 7, 21 and 60 days. That's how it sticks.

Your progress, XP, ranks, achievements and knowledge map are saved to your profile and follow you across devices.

The same lessons, for your AI assistant

Connect the lessons to Claude, ChatGPT or Cursor. Your assistant looks things up here instead of the open web, and uses the same terms you've learned. The connector is included in every plan and reads whatever is open to you.

See pricing

How it works

Why do the bumps on my rock look dented in?

searches the lessons search("bumps dented in, normal map")

reads the section fetch("light--colors")

Answers from the lesson and links to the section:

The normal map's green channel is flipped: Blender writes it one way, Unreal reads it the other. Normals and light

How the lessons are made

AI drafts the lessons and a person checks them. We'd rather say so up front.

SourcesEngine documentation, studio talks, books and articles. Each lesson draws on two to five, listed at the end of the page.
NotesWhat the sources say, which numbers they give and where they disagree.
TextWritten from the notes, not from the model's memory: one idea at a time, with demos and everyday examples.
EditorA second pass with fresh eyes: mistakes, filler, unclear passages, the arithmetic in the examples.
A personThe author reads the lesson, answers its questions and makes corrections.
PublicationThe lesson goes live. Spot a mistake? Select the text and send a note: reader questions go straight to the author.

Questions

Were the lessons written by AI?

Yes. AI drafts the text from sources, with research notes and a second editing pass. Then a person reads and corrects every lesson.

Why not just ask a chatbot?

A chatbot answers the question you ask, and a beginner doesn't know what to ask yet. Courses give you an order. A chatbot also answers differently each time and sometimes makes things up; here the text stays the same. And it won't check what you remember — the questions and spaced review do.

Do I need to know anything first?

No. Neither school math nor programming: every idea you need is explained from the start, one at a time.

What's free?

Signing up and some of the lessons. The rest opens when you buy a course or a section, or subscribe — see the pricing page.

Try the first lesson

It's free to sign up, and some lessons are open right away.

Start for free

See pricing

How games work, from the ground up

Who it's for

You're starting from zero

You're making a game with AI

You already work in games

Where do you want to start?

Start here

Graphics

Art and worlds

Code and math

Design and release

Sound familiar?

The bumps on your rock look dented in

A bullet flies straight through a wall

The camera lurches when it starts to move

Demos you can play with

What a lesson looks like

Why the face toward the sun is brighter

What's inside

Questions come back before you forget

The same lessons, for your AI assistant

How the lessons are made

Questions

Try the first lesson