HDRI shadow
How to achieve shadows with a single HDRI
in Unreal Engine 4.18 Unreal Engine



Ok so this is my first ever tutorial so bear with me! ;)
You can try the following with your own scene or you can download the tutorial scene from here:
HDRI_shadows_tutorial.zip (40Mb)

You will need the followings in your scene

- Lightmass Importance Volume covering your important area
Lightmass Importance Volume
- Lightmass Portal(s) covering your opening(s)
Lightmass Portal
- Post Process Volume
Post Process Volume
+ for better result: Reflection Capture

You don't want autoexposure in your scene that will change regarding how bright area you're looking at, so
in your Post Process Volume / Lens / Exposure set both Min/Max Brightness to 1

Post Process Volume - Exposure

Also for a clean result we'll turn off Ambient Occlusion by setting its Intensity to 0

Post Process Volume - Ambient Occlusion

And finally we'll set Post Process Volume as Unbound to effect the whole scene

Post Process Volume - Unbound

Import your HDRI image into your scene.
In my scene I used 047-free-hdri-skies-com.hdr
In the HDRI's details uncheck sRGB and set Mip Gen Settings to NoMipmaps

HDRI Import

Select your SkyLight, set it to Static.
Change Source Type from SLS Captured Scene to SLS Secified Cubemap.
Grab your HDRI and place it into the Cubemap slot.
Change Cubemap Resolution from 128 to 1024 and set the Intensity to 5 for a start.


If you want to visualize/see the HDRI in your scene as a "skydome",
please follow Rag3DVIZ's beautiful tutorial.

On the surfaces (walls), where you expect shadows to appear,
set the lightmap resolution to 256 or higher!
In my scene all walls have 1024 lightmap resolution on their inner(!) faces!

Lightmap resolution

In your World Settings use the following setup:

World Settings
Static Lighting Level Scale - DETAIL
Num Sky Lighting Bounces - more bounce information, such as color bleed and lightness
Indirect Lighting Quality - QUALITY (cleaner result)
Indirect Lighting Smoothness - more detailed lighing information / less blurred

Set your Lighting Quality to Production and click Build.


This is my result:


...and from this on, it's only Post Processing!

I set Exposure to 2 to get more contrast.
And used a LUT file to get more contrast/style.
Great tutorial by Epic: Using Lookup Tables (LUTs) for Color Grading
All I used was Curves and Brightness/Contrast


Final results:

Final 01

Final 02

Final 03

I hope it will be useful for someone...

Get in Touch

Drop me a line if feeling so.