More on De-lighting

Delightful! GET IT.

I mentioned in my last post that I used a quick and dirty method to de-light my albedo texture. 

To quickly recap, I used Substance Painter to bake all my 'mesh maps'. These are things like normals, height, ambient occlusion (AO). I used the Ambient Occlusion on a new layer, inverted the colors, and set to Linear Dodge blending mode. This is effectively 'canceling out' the real world shadows.

I kinda got away with it for the purposes of the last post. It really helped that I happened to shoot this object on an overcast day with no harsh lighting. Plus, Zephyr has some pretty powerful color correcting tools when it bakes the texture.

If you're keen, however, you'll notice that this method is not accurate and left some shadows behind:

Why? This method is only as accurate as Substance Painter's AO baking tool is. The AO baked from the high res geo might not truly match the real world shadows. I suspect that the areas I've circled did not have the same height difference in geo, or perhaps the scan was simply less accurate in those spots. 

Is it worth further fixing? Perhaps. This article does a great job explaining what proper delighting actually is. 

• I could manually correct some of the shadows in Painter or even Photoshop. 
• I could take this shader into Substance Designer and use the more powerful node based shader system to further tweak the albedo map. 
• There is also a delighting tool built in Unity that has good reviews.
• If I was dealing with extremely harsh shadows (such as on a sunny day) there is a more complicated process that has been done. First, proper documentation on location is needed. The exact lighting is then rebuilt in a 3D software. Then, because the shadows were accurately recreated, they can be accurately 'cancelled out'. (*find source video on this)

With all that in mind, I think it's worth pointing out that the accuracy of delighting your albedo map also depends on the accuracy of your final rendering method... so if you are old school realtime and you will be baking AO into a 'diffuse' map anyways, these steps are a waste of time. 

I think for my own work I will play by ear a bit to fine tune exactly how much accuracy is needed. Perhaps for background objects this is less important, or perhaps it will always be a case by case basis. 

Either way, the old rule of good input == good output definitely applies here. Shooting with diffuse lighting will eliminate much of this process anyways.