#mxao tips

Good morning (or afternoon) to you too, lovely anon!

Because of the way IL is calculated it has to be turned on via the Preprocessor Definitions section in ReShade.

There are two ways to do this. Either works just as well as the other, so it’s personal preference.

1. If you look at the top screenshot in this MXAO tutorial you’ll see some extra lines inside the Preprocessor Definitions box that is in the Settings tab. Everything with MXAO at the beginning is what you need to add in. 

Strictly, I believe only ENABLE_IL is needed for IL, but they all do good things for the MXAO shader so it’s worth adding them all. Generally 0 = off, and 1 = on, except for...

The two that say MIPLEVEL relate to the quality of both the ambient occlusion (the shadowing you’re most familiar with) and the IL. 0 is the best quality, 2 is the least, 1 is in the middle. I honestly don’t know if there’s a discernible difference to how it looks, but I keep them both on 0 because I can. If you struggle with performance, consider dropping them to 1.

SMOOTHNORMALS is meant to help with some of the awkward angles you can see when MXAO shadows blocky models. It seems to have more of an effect in non-qUINT versions of MXAO. 1 = on, 0 = off.

TWO-LAYER enables finer control and splits AO into Fine and Coarse. To my eyes fiddling with either of the multiplier values produces exactly the same effect, but the Fine AO Scale does something different... I’m not exactly sure what but it’s another value to play around with if you’re looking for perfection. 1 = on, 0 = off.

BACKFACE is to do with whether the backs of objects will be lit or not, and enabling it is meant to increase realism (at the cost of performance). This setting isn’t used in newer versions of MXAO, so your version may not use it. 1 is on, 0 is off.

The way to check if your version uses a particular preprocessor definition is to open up the mxao.fx file in Notepad++ or similar and look at the top section. All of the commands above will be listed there (using slightly different formats to how you list them in the gui, but you’ll be able to tell which is which). If backface isn’t there, your version doesn’t use it.

Which brings me to the second way you can enable IL (and these other commands).

2. Directly in the mxao.fx file. You can go in and edit the lines right in the file with your zeros and ones, save, and you’ll never have to worry about adding them to the gui. This is, arguably, much quicker and easier, and it persists wherever you paste that mxao.fx file (if you use ReShade in different games and use the same shaders, just use your edited shader and you’re good to go). It also means you don’t have to guess which definitions are applicable to your version of mxao because they’re right there.

With all the talk about MXAO in ReShade atm, I thought I’d post my settings in case anyone wants a starting point.

I use ReShade 3.4, I play in windowed mode, and I create my presets while in tab mode.

The top picture shows the preprocessor definitions you need to add in the Settings tab. After adding them, you need to hit ‘Reload’ at the bottom of the Home tab.

The second picture shows my current settings. This provides what I consider to be a pretty natural-looking MXAO, a decent balance between being natural and actually being able to see it. Too heavy settings just look awful imo, what you should strive for is something that compliments rather than overpowers.

You’ll see I use indirect lighting (IL) with these settings. The third picture shows my how my settings look in debug mode. Look at the planters and the fountain on the right -- do you see some colour at the bottom? That’s the IL. It adds light bounce-back against certain surfaces. Compare it to the bottom picture, which has IL disabled. Look under the bench on the left, see how the wall underneath it is darker? That’s because there’s no light bounce-back. IL provides a more realistic implementation of how light and shadow works, but it’s entirely up to you if you want to use it or not. I particularly like it in TS4 for the colour saturation, and the way it makes things feel more alive. It reflects back light in the colour of the things around it. So, for example, your kitchen counter might reflect back the colour of the cupboard doors.

Example of IL in action here.

Let me know if you find this useful.

Note: These settings are for ReShade 3.4 and the MXAO shader distributed with it. If you have a different version of the MXAO shader the preprocessor definitions may be different. In particular, the last 2 in the list may not exist. You can check which preprocessor definitions are appropriate for your version of ReShade and MXAO by opening the MXAO.fx file (that’s the shader itself) and looking in the preprocessor settings at the top.

In addition, MXAO has, at some point around 3.1, changed the way some of the values look. If your version doesn’t have a drop-down box for quality, for example, you will have to adjust accordingly.