How to generate a fake top lighting effect?

Question

How can I generate a fake top lighting effect for a stylized game asset.

Answer 1

Lighting effect aren't recommended for PBR games, but it can be useful for games running on old hardware or mobile games to save calculation by displaying the assets in shadeless/unshaded.

• To create this shader, add an emissive shader on your high poly.
• Use an Input > Texture Coordinate and use the Normal input. This Input colors the faces depending on their orientation relative to the world (this means the rotation must be applied with Ctrl + a).
• Connect it to a Converter > Separate RGB and use the Blue channel.
• By default only the bright values are visible, to display the dark values add a Color > MixRGB and set it to Screen.
• You can add a fake Global Illumination effect by adding another Screen node.
• To bake your texture on the low poly use the Emit bake mode. You will find more informations about baking with Cycles here: https://blender.stackexchange.com/a/13509/23134
• (optional) Blender's viewport and tools work in sRGB. If you want to export it to work in Photoshop or GIMP you will need to convert it to Linear, for that add a Color > Gamma and set the gamma value to 2.2.