Unreal Engine 4.26 Preview released

Cinematic and Virtual Production Updates:

• Movie Render Queue Improvements (Beta). New Movie Render Queue gives you new options to control its operation and to customize the images it produces.
  • Render passes. You can now choose to export media using only selected render passes, including ObjectId, Motion Vectors, Z-Depth, World Position, World Normals, Ambient Occlusion, and Reflections. This opens up a wide range of possibilities for compositing images generated by Unreal Engine in external applications.
  • Runtime rendering. You can now use the Render Manager to generate still or sequence images at runtime, not just in the Unreal Editor.
  • Pro codecs. The Movie Render Queue now supports pro codecs, including Apple Pro Res and Avid DNxHR.
  • Multi-channel EXRs. You can now export media in multi-channel EXR format, packing multiple channels such as base color, ambient occlusion, and reflections into a single image file.
  • EXR compression. When you export to EXR format, you can now compress the resulting files using your choice of compression formats.
  • Final Cut Pro EDLs. Create Edit Decision Lists (EDLs) in an industry standard format.
• Sequencer Improvements:
  • Nonlinear Animation. This collection of features improves Sequencer tools to create, modify, join, and blend animation assets in order to quickly author new animation cinematics for virtual productions and games. This will reduce the need to use external tools for animation authoring and blending. These improvements include blending the root motion of skeletal animation sequences; joint matching for better blending and placement; skeleton animation preview for precise placement; and Control Rig FK / IK integration.
  • Quality of Life Improvements. There are many quality of life improvements in Sequencer this release, including UX/UI, pipeline, evaluation, and Take Recorder.
  • Pro codecs. Sequencer can now play back media using pro codecs, including Apple Pro Res and Avid DNxHR.
  • Camera Cuts. Take Recorder can now record camera cuts.
  • Editor scripting. You can now use Blueprint and Python to access and control selections for sections, tracks, folders, and objects.
  • High Quality Media Export (HQME) Workflow Improvements. Several workflow improvements were made to HQME including: support for Final Cut Pro XML ELDs; open Color IO integration; run-time support for implementation into users' projects; and support for the render farm plug-in Deadline on the Epic Marketplace.

• OCIO support in Editor (Beta). You can now guarantee a consistent color space for all the work you do in Unreal Engine by applying an Open Color IO (OCIO) profile to the Unreal Editor viewport and to the media you export through the new Movie Render Queue.
• 3D Text Improvements - additional bevel options, a 3D outline mode, and joined cursive letters for Arabic text.
• In-Camera VFX Improvements to Color Correction Volumes so that more volumes can be in a scene.

• Timecode Improvements (Beta)
  • You can now export media with an embedded timecode.
  • When recording timecode, missing frame errors are logged with a timestamp.
  • When evaluating the last frame data of the recording, the engine’s delta times and the action’s delta times are now smoothed to remove jitter.

Datasmith and Import Updates:

• Datasmith Interop - added support for more third-party design applications. Remember to download and install the new version of the export plugin for your software, if needed.
  • Added support for Autodesk Navisworks
    Exporting from Navisworks uses a similar workflow as other Autodesk applications. You download and install the Datasmith Export plugin for Navisworks. Once installed, you should see an Unreal Datasmith menu option in your Navisworks UI. Open this ribbon, and use the Datasmith Export button to export your scene to a *.udatasmith file. You can then import this file into the Unreal Editor.
    The export plugin supports Navisworks 2019, 2020, and 2021.
  • Rhino. To continue improving the quality of our data translation process, we’ve created a new export plugin for Rhino. Once you download and install this plugin, you should see a new option in Rhino that you can use to save or export your scene as a *.udatasmith file. You can use any of the File > Save As..., File > Export Selected…, or File > Export With Origin… commands. Once you have your *.udatasmith file, you can import it into the Unreal Editor.
    As part of this change, we can now support importing custom user text that you set on your scene objects in Rhino into Datasmith Metadata.
  • Revit. Added support for Revit 2021.
    (You’ll also notice new options in the Ribbon for connecting and synchronizing with an Unreal Engine instance. This workflow depends on other upcoming developments before it will be beneficial. For now, use the same file-based export process you’re used to from previous releases.)
  • SketchUp. Added support for SketchUp Pro 2020.
  • Multi-file import exposed to Python. You can now batch import multiple CAD files, combining them into a single Datasmith scene. Use the new unreal.DatasmithSceneElement.construct_datasmith_scene_from_cad_files() function.
• USD Stage improvements (Beta). 
  • Blend shapes. Blend shape animations in the USD file are now translated into morph targets in Unreal.
  • Lights. USD lights that are based on the UsdLuxLight schema are now translated into Unreal. We convert UsdLuxDistantLights as Directional Lights, UsdLuxRectLights and UsdLuxDiskLights as Rect Lights, UsdLuxSphereLights as Point Lights, and UsdLuxDomeLights as Sky Lights. USD light intensities are unitless, and are converted as physical light units based on approximation formulas provided by Pixar.
  • New importer. The old USD importer module has been deprecated and replaced with a new USDStageImporter module that is based on the logic used by the live USD stage. This allows you to import your USD scene into native Unreal Actors and Assets with equivalent fidelity to the results you see in the live USD stage.
• LiDar Plugin Improvements

Physics Updates:

• Chaos replaces PhysX by default. The Chaos physics system is now considered production ready, and replaces PhysX as the default system.
• Chaos Cloth. By default, the Chaos Cloth solver will replace PhysX for cloth simulation in use cases ranging from mobile to high-end cinematics.
• Chaos Vehicle (Experimental). By default, the Chaos Vehicle physics system will replace PhysX for developers who need real-time vehicles with real-world physics simulation.

Rendering Updates:

• Volumetric Clouds. The new Volumetric Clouds Actor provides a material-driven real-time cloud rendering system. The component requires a material to work. You can use the default one found in Engine/EngineSky/VolumetricClouds/M_SimpleVolumetricCloud.
• Sky Atmosphere Improvements. The Sky Atmosphere component introduced in 4.23 continues to see improvement with this release with the following:
  • The sample count used to trace the atmosphere is now scalable and can be controlled using a slider. This is important for generating the LUTs, or simply running per-pixel tracing.
  • Sky can now receive shadows from opaque meshes and volumetric clouds. This is enabled from the Directional light with Cast Shadows on Atmosphere and Cast Cloud Shadows. Distance from which opaque shadowing happens is controlled using the Dynamic Shadow Distance.
  • You can now enable a high quality mode for cinematics. By default, the Sky View and Aerial Perspective LUTs are used to render distant sky and aerial perspective at a lower resolution. You can tweak their visuals using commands.
• Real-time Sky Light Capture. Sky now has a Real Time Capture mode when set to Movable. It improves on, and is faster than, the Sky Recapture Blueprint node by performing all computations on the GPU without any CPU readback.
• Sun Sky Plugin Performance Improvements. The plugin now takes advantage of the latest improvements to sky light with real-time capture. Previously, the sky environment maps could only be captured and convolved in editor with interpolation happening at runtime. This would result in visual discrepancies between the visual sky and diffuse and specular lighting on meshes. Real time capture improves performance and visuals by capturing SkyAtmosphere, Volumetric Cloud, and SkyDome meshes with a material that is tagged as IsSky.
• Environment Light Mixer. The new Environment Light Mixer contains a level’s active Sky Light, Directional Lights, Sky Atmosphere, and Volumetric Cloud components in a single panel for ease of editing.It can be used to display a minimal or entire set of properties for each component. It can also be used to spawn a component into the level.
• The Environment Light Mixer can be opened from the main menu under the Window dropdown.
• GPU Lightmass. Lightmass is getting an upgrade using a progressive lightmapper that works on the GPU. It supports full material representation, taking into account some things ignored by Lightmass, such as Vertex Colors. GPU Lightmass is based on ray tracing technology, which currently requires Windows and a DXR capable card supported by NVIDIA. As other vendors support ray tracing, UE4 will not be tied to a specific operating system or graphics card.

• To enable GPU Lightmass:
  • Enable Ray Tracing and set the Default RHI to DX12 in the Project Settings. (Requires a DXR capable graphics card with Windows 10 build 1809 or later.)
  • Enable Virtual Texture Lightmaps project setting for real-time preview in the editor.
  • Enable the GPU Lightmass plugin.
• GPU Lightmass is now available through the Build menu.

Additional Notes:

• You can also use the r.GPULightmass.* console commands to adjust GPULightmass settings and ToggleLightmapPreview command to start GPU Lightmass in the editor.
• GPULightmass throttles itself when Realtime is enabled in the Level Editor viewport.
• Recommended to set r.RayTracing.ForceAllRayTracingEffects 0 in the editor to disable all ray tracing effects. This helps give more resources to GPULightmass and avoids some confusion between features, such as ray tracing soft shadows rendering on top of lightmaps.

Water System (Experimental). The water system from Fortnite has been brought over to Unreal Engine. It can be used to create oceans, rivers, and lakes that seamless blend between one another and the landscape terrain. It uses an editable spline system to generate water tiles that work with landscape terrain.

To start using the Water system, enable the Water and Landmass plugins.

• Hair and Fur Simulation. Hair and fur features within Unreal Engine are now considered production ready. This release sees the following features, improvements, and updates:
  • Fur and Feather
  • Support for LODing of hair.
  • An in-editor cards and mesh generation system for lower end hardware (experimental).
  • Wider feature compatibility, such as DOF, fog, and more.
  • An Asset Groom Editor that enables you to:
    • Make fine adjustments to the groom, such as clipping strands to a certain length, increasing strands/root/tips size, and more.
    • Setting up LODs, physics, and motion interpolation.
    • Generating hair cards and setting up meshes.
    • And managing materials for various representations.
  • Many optimizations to performance.
• Ray Tracing Improvements. The following ray tracing and path tracing improvements have been made for this release:
  • Ray Tracing Improvements:
    • Extended translucency support
    • Support for Thin Translucency shading model
    • Subsurface improvements
    • Two-sided foliage support in RTGI
  • Path Tracing Improvements
    • Two-sided foliage support

• Material Layering System. This release sees the system become production-ready and is enabled by default now.
• Gen 5 Temporal Anti-Aliasing (TAA) (Experimental). The 5th generation of consoles and its GPU performance enable new millisecond budgets for the features of the renderer in frames. One feature that has been heavily constrained by performance on current-gen hardware is Temporal AA and it's Temporal Upsampling capability released with dynamic resolution in Unreal Engine 4.19. 

For full update list, visit Unreal Engine page.