This tutorial shows you how to make an AO map. You will learn how to make an AO map in Affinity Photo. The final composite and render was done in Blender.
AO Map
I will be using a tileable texture I made in a previous tutorial
I duplicate the image and rename the layer to “AO”
I open the Adjustment panel (under the Window menu) and under the HSL panel, choose Desaturate
I lower the saturation to -100-percent and the luminosity to around 50-percent
I then open the Levels and choose the Default option
If I make the image brighter, the surface will appear well-lit
If I make the image darker, the surface will appear more in shadow
I will adjust the Gamma level to around 1.5 to slightly darken the image
I can now export this image as a PNG (JPG will also work)
Blender
In Blender, under the Shading Workspace, I import the Color map, Normal map, Roughness map, and the AO map
I make sure to change the color space for all the maps (except the Color) to Non-Color
Normal Map Tutorial: https://www.youtube.com/watch?v=xJ-Lg4ru3go
Height & Roughness Tutorial: https://www.youtube.com/watch?v=YEFqKvfz79g
For the AO Map, I add a Mix Color node and connect the AO map to the B input and Color map to the A input
I change the Blending Mode to Multiply
I add a Shader to RGB node and Diffuse BSDF node to control the AO map
I connect the Shader to RGB node into a Color Ramp and connect the Color Ramp to the Factor of the Mix Color
I then switch the color stops and now I can use the Color Ramp to adjust the AO