UE4 – Quick fix for normal map encoding

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:

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

Annotation 2020-09-06 160838

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

  1. Open the normal map in Photoshop
  2. In the Channels panel, select the Green channel
  3. Press Ctrl + I,
    Or Select Image > Adjustments > Invert
    To invert the green channel.
  4. Save the texture and reload into Unreal Engine.
    Annotation 2020-07-06 233156

Inverted normal map:Annotation 2020-07-06 232554

Fixed normal map:Annotation 2020-07-06 233036

Related:
UE4 Bump map

UE4 – Technical model visualization tips

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:

  1. 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….
    Annotation 2020-07-06 195120
  2. Improve the accuracy of environment lighting by increasing the Cubemap resolution of the Skylight:
    * use powers of 2 values i.e. 256, 512, 1024….
    Annotation 2020-07-06 202415
  3. 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
    Annotation 2020-07-06 204022
  4. Use a high degree of tessellation (subdivision) for the models pre-import.
    Simpy put:
    Use high quality models.
  5. 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
    Annotation 2020-07-06 210030
  6. 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
    Annotation 2020-07-06 211152Set the material Shading Model to Clear Coat and use a ClearCoatBottomNormal input node to add a normal map for the underlying layer:
    Annotation 2020-07-06 221027

 

Related:

  1. UE4 – Lighting calculation tips
  2. UE4 HDRI lighting
  3. UE4 – Enable DXR ray-traced reflections 

UE4 – Enable DXR Raytracing

Software:
Unreal Engine 4.25

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

  1. Project Settings:
    Platforms > Windows > Targeted RHIs:
    Set Default RHI to DirectX 12
    * RHI = Rendering Hardware Interface
  2. 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..
  3. Post Process Volume > Rendering Features > Reflections:
    Set Type to: Ray Tracing
  4. Post Process Volume > Rendering Features > Ray Tracing Reflections:
    Set Max Bounces to more than 1 if needed

No DXR Reflections:
Annotation 2020-07-05 011317

DXR Reflections on a GTX 1070 GPU:
Annotation 2020-07-05 020433

 

Related posts:

  1. UE4 Light calculation tips
  2. UE4 HDRI lighting
  3. UE4 – Technical model quality tips

UE4 – HDRI Environment & Lighting

Software:
Unreal Engine 4.25

Annotation 2020-05-20 162811

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

  1. 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)
  2. 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
    Annotation 2020-05-20 153925
  3. Drag a Lights > HDRI Backdrop object to your level:
    Annotation 2020-05-20 154657
  4. In the HDRIBackdrop details, select the wanted Cubemap:
    Annotation 2020-05-20 155212
  5. > 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.Annotation 2020-05-20 160338

 

Related:

  1. Sun & Sky link
  2. UE4 Architectural Glazing
  3. 3ds max & V-Ray to UE4 Datasmith workflow
  4. Preparing an FPS project for archviz
  5. UE4 – Archviz Light calculaion tips