How do you combine cavity and AO map

Duckmamoll

Hello,

I was watching a zbrush tutorial in which the person teaching baked his AO and cavity map under xnormal, then cuts to substance painter, in which he uses as his AO a map that he claims to be a combination of both, I believe it is to have extra details. How do you combine them? I have very little knowledge of GIMP (and I don't have photoshop), or if anybody knows a way to combine them under substance designer, that's a software I know how to use without any issue. Either way I'd be very thankful if anybody can explains the combining process to me.

Thank you for reading

Alex_J

they are both grayscale (black and white) images. So you can can combine them using multiplication operation. I am not familiar with gimp but just google gimp "multiply layers" and I'm sure you find specific instructions

Duckmamoll

I obviously guessed that's how you'd do it. But I guess I was also asking, what's the best blend mode for it and what kind of results I need to get. I found I can do it under paint.net and I used an overlay layer at 80/255 opacity, but idk what results i'm supposed to get

Alex_J

https://www.clipstudio.net/how-to-draw/archives/154182

here's an explanation.

you should have the two layers completly blended together so that you get the full AO plus the cavity details. If you are messing with the opacity you wont be able to accomplish that. I suspect you misunerstood the term "multiply". its a precise term, not generic. It is a common operation for editing images.

Alex_J

https://www.photoshopessentials.com/photo-editing/layer-blend-modes/multiply/

that first link it kinda shitty explanation. this is better.

note that its talking about photoshop but multiply exist in all your software

Blaizer

Arnother one very useful with displacement maps, and greyscale maps in general is the darken mode. You should experiment a bit though.

Duckmamoll

Hey thanks, I was already aware of what blendings modes are and what they mean. But when you state I shouldn't mess with the opacity, what happens with either darken or multiply and 100% opacity is that the dark parts of the cavity makes cavities way too dark and makes the AO bad looking imo. But maybe extremly dark AO maps is not a problem and I'm just wrong

Alex_J

Just go ahead with the textures as is and view it in your final render engine. Then you can tweak those maps to your liking and see directly what the result will be.

I'd keep a copy of the cavity and AO not combined for safe keeping. Depepnding on what shader you use you may be able to use them separately.

kanga

How I understand it is that baking a cavity map produces a displacement map. I could be wrong. Using the cavity map as an image map and doing what Alex Javor says by sloting it into a shader as a layer and using 'multiply', then playing with the opacity really adds depth to the model in substance painter.

Alex_J

https://marmoset.co/posts/creating-realistic-skin-toolbag-saurabh-jethani/

this covers the use of cavity map that i was imagining ^

basically it works like an alternate AO map. ANd of course if OP is combining with AO, then it's just AO map. But in toolbag shader you can use some  specific functions designed for cavity map which work well for realistic character rendering. Help bring out small skin details and such.

Ghogiel

Since you are trying to use it in substance in some way, is there really any need to destructively add the cavity into the AO map, is it not feasible to import the cavity as a resource then just use it however you want in a layer setup to get this extra detail you mention?