ue – Oded Maoz Erell's CG Log

UE4 – Quick fix for normal map encoding

Posted on July 6, 2020October 31, 2020 by Oded Maoz Erell

Software:
Unreal Engine 4.25 | Photoshop 2020

Quick UE normal map tip:
If you load a normal map into a UE material and the result appears inverted, i.e. holes instead of bumps or the other way:

The quick fix:

In the texture settings, check the Flip Green Channel option and save it:

The deep fix:
* This can be performed an automated action on multiple files

Open the normal map in Photoshop
In the Channels panel, select the Green channel
Press Ctrl + I,
Or Select Image > Adjustments > Invert
To invert the green channel.
Save the texture and reload into Unreal Engine.

Inverted normal map:

Fixed normal map:

UE4 – Technical model visualization tips

Posted on July 6, 2020July 7, 2020 by Oded Maoz Erell

Software:
Unreal Engine 4.25

This post is a summary of the tips given by Epic Games technical-artist Min Oh in his GDC 2017 lecture about improving photo-realism in product visualization, more specifically, how to render high quality surfaces.
I recommend watching the full lecture:

Render sharper reflections by increasing the Cubemap resolution of reflection captures:
Project Settings > Engine > Rendering > Reflection > Reflection Capture Resolution
* use powers of 2 values i.e. 256, 512, 1024….
Improve the accuracy of environment lighting by increasing the Cubemap resolution of the Skylight:
* use powers of 2 values i.e. 256, 512, 1024….
Improve screen space effects accuracy like screen space reflections by setting the engine to compute high precision normals for the GBuffer:
Set Project Settings > Engine > Rendering > Optimizations > GBuffer Format to:
High Precision Normals
Use a high degree of tessellation (subdivision) for the models pre-import.
Simpy put:
Use high quality models.
Improve the surfaces tangent space accuracy, and as a result also the shading/reflection accuracy by setting the model’s static mesh components to encode high precision tangent basis:
Static Mesh Editor > Details > LOD 0 > Build Settings > Use High Precision Tangent basis
Creating materials with rich dual specular layers by enabling material clear coat separate normal input:
Project Settings > Engine > Rendering > Materials > Clear Coat Enable Second Normal
Set the material Shading Model to Clear Coat and use a ClearCoatBottomNormal input node to add a normal map for the underlying layer:

Related:

UE4 – Enable DXR Raytracing

Posted on July 5, 2020July 6, 2020 by Oded Maoz Erell

Software:
Unreal Engine 4.25

Steps for activating DXR Ray-tracing in a UE4 project:

Project Settings:
Platforms > Windows > Targeted RHIs:
Set Default RHI to DirectX 12
* RHI = Rendering Hardware Interface
Project Settings:
Engine > Rendering > Ray Tracing:
Check Ray Tracing
* Requires restarting the editor, and may take a while to load the project afterwards..
* I’m actually not sure if the reason for delay in re-launching the project is a full re-build of the lighting or compiling shaders..
Post Process Volume > Rendering Features > Reflections:
Set Type to: Ray Tracing
Post Process Volume > Rendering Features > Ray Tracing Reflections:
Set Max Bounces to more than 1 if needed

No DXR Reflections:

DXR Reflections on a GTX 1070 GPU:

Related posts:

UE4 – HDRI Environment & Lighting

Posted on May 20, 2020July 4, 2020 by Oded Maoz Erell

Software:
Unreal Engine 4.25

Creating HDRI environment backgruond and lighting* in UE4:
Note:
Lighting using a panoramic HDRI background is also referred to as IBL – Image Based Lighting.

* The example HDRIs in this post are from www.hdrihaven.com

Import HDRI environment file.
Note:
The file must be saved as a *.hdr file and not *.exr because AFAIK that’s the only way UE4 will recognize it as an HDRI environment and encode it as a Texture Cube (cube map)
Enable the HDRIBackdrop plugin:
Go to Edit > Plugins
Type “HDRI” in the search field to locate HDRIBackdrop and enable it.
* You’l have to restart the UE Editor before using the plugin
Drag a Lights > HDRI Backdrop object to your level:
In the HDRIBackdrop details, select the wanted Cubemap:
> Set the HDRIBackdrop‘s Intensity (self explanatory..).
> Rotate the HDRIBackdrop around its Z axis to set the environment’s direction.
> Set the HDRIBackdrop‘s Size.
* Make it larger than your whole scene,
And if Use Camera Projection is unchecked make it also large enough so that noticeable objects in the HDRI image will be distant enough as to not move incorrectly when you strife.
* When Use Camera Projection is activated the Size property has no effect.
> If Use Camera Projection is unchecked, set the Projection Center Z value to define the background image height below which it is projected as a flat ground.
> Lighting Distance Factor defines ground projection area that will appear to receive shadows from your scene objects.
* Set this attribute to 0 in-order to turn off the ground projection shadow.
> Use Camera Projection:
Activate this option to get a traditional infinitely far background with no flat ground surface projection.

Related: