DFAO radius and intensity

Hey everyone, I have a problem to see the effect from DFAO.
Did everything with setup, but the effect is soo poor and barely visible opposite to the video where the objects are moving and there is a big radius of AO around the objects.
How I can increase the contrast/intensity to achieve that effect?
In Skylight the Contrast setting isn’t doing anything.

Screenshots with DFAO and a simple Multiply in Photoshop that is looking better.


DFAO only affect ambient lighting. You are looking scene under direct influence of sun. Sun is multiple times stronger than skylight. Look shadowed parts of scene to see effect better. Usually ambient occlusion is more visible when the scene is bit more complex. Just simple plane and couple box hardly have any interesting parts.

Jenny Gore, thanks for the answer. Actually I came with that simple test after my complex scene where I have barely visible effect too… Is any way here to increase that effect, why the contrast isn’t doing anything? I’m playing with 10. Basicaly I’m looking the same result as on video…

JennyGore is right. Shut down the sun, and you should see it a lot clearer. As for contrast, there’s a very dirty trick, which I absolutely do not recommend using. Set your contrast in Skylight DFAO settings to negative value :slight_smile: Also play with the spread radius. But mostly I would say it’s just being washed out by the sunlight.

and just a point from my test the AO is here, it’s not about the direct lighting or anything, it’s just simply barely visible, but the screen from photoshop you can see the stronger effect… So I want to achieve that effect.

If it’s not about direct lighting then just remove it from scene. AO does not have any effect for direct light like sun and never should have. Just look corners in real world in direct light. You don’t see any AO.

ok, thanks guys for the answers, but I didn’t get it… If I lower intensity of sunlight, the lighting will be too dark, so why I need that? Epic is recommending using directional light intensity from 5 to 10, I’m using 8, it’s not crazy.
What I did, I lower Skylight intensity to 0.04 to get darker shadows. And I’m using LPV by the way, maybe it is affecting each other somehow? I lower LPV intensity value, but it not helped. If I completely turn off LPV, the shadow will be black, so I made that on second screenshot and increased Skylight intensity to 0.8

I clearly don’t see AO in shadow parts with LPV.

1st LPV off, I can’t see DFAO on lit, but on lighting view I can see it barely. On shadow parts the effect is present, but on lit there aren’t any…

I never tried using LPV with DFAO, so maybe this can be the issue. If you want to get really tight AO in the corners, try playing with SSAO instead, bump its intensity up (you can find it in your post process volume). What could really help your shading is HBAO+, but it’s not implemented in UE4 by default, you’d have to build the version (you can find info in NVidia thread).

Maybe there is bug in LPV. First screenshot has good angle, use that when you try to see any AO effect. Looking directly lit parts will not show strong AO.

thanks a lot for the answers and workarounds, I’ll continue to play with it to achieve somewhat result I want. I found a ref of something I’m looking for, you can check just cause 3 latest vids here and here
look under the cars and big objects, there is a very subtle effect of brownish AO on the lit side of objects, it’s like dynamic GI combined with DFAO.
The thing you’re right that with LPV turned off DFAO is more visible, but I can’t not use LPV because my project using only realtime lighting without lightmaps… And it’s a little frustrating, that in UE4 there is very poor support for dynamic GI. I read old topics on forums about that, but it seems no very big progression there still from 4.8.
will try to update if I’ll find something.


I can see AO only on the shadowed part. I have never used LPV combined with DFAO so I can’t say is there bug or not with them combined. But it’s not bug that AO is not showing under direct illumination.

Jenny, there is a warm brown haze around the object on the light side. Just watch on the moving objects, it’s most obvious. But it is present on static too.
I agree with you tho that AO on the light side by nature isn’t clearly visible, but I’m not looking for the realistic effect, it’s boring looking.
The same warm brownish AO effect is in GTA5 and other latest open world games, it is integrating object into the world nicely and the car isn’t flying on the ground even at the light.


maybe there is an alpha under the car creating such effect, but I believe it’s not. But maybe it’s a ground material property increasing AO intensity around the object. Maybe need to do something with materials, but didn’t found nodes directing to DFAO…

Cars are a very special case. You are right, that dark shadow is a must if you want your cars not to float. The solution I use now is just link decal with soft alpha underneath the car (what you mentioned). Now, this goes out of the window, the second you have wet ground, since reflections will overpower that decal, and you car will still “float”.

DFAO does the trick really well, but it cannot be used with moving objects, thus I am stuck with that decal solution.

Would be nice to hear if anyone knows of a solution to this.

BTW, in the roadmap there’s a mention of dynamic area shadows for skinned objects, maybe that will help you.

Oh, and also I would still suggest you look into HBAO.

Here’s an example

As you can see it adds quite a bit of depth to the scene (still won’t solve the car shadow issue though). It’s been used in games like Watchdogs, I believe, perhaps in GTAV too, but I’m not certain.

DFAO works with moving objects but not with skinned. Cars only have spinning wheels but those does not invalid distance field volume texture at all.

HBAO isn’t solution to this. It’s screenspace technique with lower range than DFAO.

Yeah, I know. As I said, it won’t give you these kinds of shadows, but it will give scene just a bit more depth, which is maybe what Teho was looking for.

HBAO+ is a nice feature, but I need to build it as mentioned by BrickTop. I managed to work everything with LPV and inside it there are some good settings for diffuse bounces and contrast, increase it and there is a depth in shadows and DFAO is looking much better. The one thing is LPV is costly and I can’t blend the apperiance of it with the rest of the scene, so I get a hard edge between LPV radius on other scene when camera is moving. Increasing the distance is creating bleedings and other artifacts plus it’s very costly to calculate… But it’s another side of the problem.

Take a look at DFGI as well. It’s also quite expensive to use in production, but it’s just another method to get some bounce lighting. May suit your needs better.