DirectX vs OpenGL Normal Maps: Unreal Engine and Unity Explained
Why your normal map looks inverted, which format Unreal Engine and Unity expect, and three ways to fix the green channel.
For Unity developers
Unity tools & resources
Tools that speak Unity: OpenGL normal maps, URP and HDRP mask maps, sprite atlases, C# easing code and assets on the Unity Asset Store.
- OpenGL normal maps
- URP & HDRP mask maps
- C# easing functions
- JSON data export
Unity essentials
The details that trip up most developers, and that every tool on this site handles for you.
Normal maps
Unity expects OpenGL normal maps (green channel points up). Set Texture Type to Normal map, and use "Flip Green Channel" for DirectX maps.
Packed textures
URP Lit reads Metallic from R, Occlusion from G and Smoothness from A. HDRP Mask Maps add a Detail Mask in B. Smoothness = 1 − roughness.
Units & axes
Unity is Y-up and Z-forward, and 1 unit is 1 meter. Euler rotations are applied Z, X, then Y.
Texture sizes
Set Max Size per platform in the import settings, and prefer power-of-two sizes for clean compression.
Data
JsonUtility and ScriptableObjects make it easy to load balancing data like XP curves and loot tables.
Selling
Unity tools and assets are sold on the Unity Asset Store.
Free tools for Unity
All tools →Normal Map Generator
Turn a height map or texture into a normal map. DirectX for Unreal, OpenGL for Unity, seamless tiling.
Open tool →Texture Channel Packer
Pack AO, roughness and metallic into one texture: Unreal ORM, Unity URP and HDRP Mask Map presets.
Open tool →Sprite Sheet Packer
Pack hundreds of sprites into atlases with trimming, padding and extrusion. Exports JSON for Paper2D and more.
Open tool →Power of Two Texture Resizer
Batch resize textures to power-of-two sizes, convert to PNG, JPG or WebP and shrink file sizes.
Open tool →Steam Capsule & Asset Generator
Create every Steam store, library and event image at the right size from one key art and logo.
Open tool →Steam Sales & Revenue Estimator
Estimate copies sold and real take-home revenue from Steam reviews, price, discounts, refunds and taxes.
Open tool →Game Name Generator
Generate memorable game titles by genre and mood, then check that the name is not already taken.
Open tool →Unity ↔ Unreal Converter
Convert positions, rotations and scale between Unity (meters, Y-up) and Unreal (centimeters, Z-up).
Open tool →Easing Functions & Curves
Preview every easing curve live and copy ready-to-use code for Unity C# and Unreal C++.
Open tool →Shop Economy Calculator
Balance prices, margins and daily profit for shop, tycoon and simulator games. Finds the price that earns the most.
Open tool →XP Level Curve Generator
Design levelling curves with linear, power or exponential formulas. Export to an Unreal DataTable or Unity JSON.
Open tool →Drop Rate & Loot Table Calculator
See the real odds of a drop after N tries and turn loot table weights into percentages players understand.
Open tool →Unity articles
More →Unity vs Unreal Coordinate Systems: Axes, Units and Rotations
How Unity and Unreal Engine differ in axes, units and rotation order, the exact formulas to convert positions, rotations and scale, and common pitfalls.
Texture Channel Packing: Unreal ORM vs Unity Mask Maps
What channel packing is, the exact channel layouts for Unreal ORM, Unity URP and Unity HDRP, why Unity uses smoothness, and the import settings that matter.