Wednesday, September 4th, 2019 Posted by Jim Thacker

Epic Games releases Unreal Engine 4.23

Epic Games has released Unreal Engine 4.23, the latest update to the game engine and development environment, introducing Chaos, its much-anticipated ‘Hollywood physics’ system.

The release also updates UE4’s new hardware-accelerated ray tracing system and Niagara particle toolset, and adds new tools aimed at VFX and virtual production work.

As ever with an update to Unreal Engine, the full changelog is huge, so below, we’ve picked through it for the features most relevant to games artists, as opposed to programmers.

Chaos: a new ‘Hollywood-quality’ fracturing and destruction system integrated with Niagara
The biggest new toolset in Unreal Engine 4.23 is Chaos, Epic Games’ much-anticipated fracturing and destruction physics system, shown in the video above.

When it was unveiled at GDC 2019, Epic Games CTO Kim Libreri described it as “Hollywood-quality physics”.

It provides a range of options for pre-fracturing geometry, including Voronoi, radial and planar fracturing, plus the option to control how sub-fractures are clustered.

Once fractured, geometry can be destroyed using Chaos’s Fields system, which makes it possible to apply a range of force types.

Individual geometry pieces can also be anchored, making them unaffected by the simulation.

As well as being generated at runtime, simulations can be calculated in advance and cached, making it possible to play back complex effects in real time.

Chaos also integrates with Niagara, Unreal Engine’s new particle simulation system, so fracture geometry can be set to emit particle-based dust or smoke.

Niagara itself gets an update, adding GPU support when sampling meshes, ray tracing support when rendering Niagara sprite particles, and increased feature partity with the old Cascade particle system.

Both Chaos and Niagara are still officially in beta.

VFX and virtual production: new virtual scouting toolset, frustum-based rendering of live footage
Film-makers also get a beta toolset, in the shape of Unreal Engine 4.23’s new virtual scouting system.

The system streamlines the process of navigating virtual sets inside Unreal Engine, with options to create camera views, bookmark or annotate key points in the level, or obtain measurements.

Other changes to the VFX tools include camera frustum-based rendering, enabling objects from live footage to receive lighting and reflections from the CG environment.

There are also updates to the Live Link plugin, for synchronising Unreal Engine with external DCC tools, and the Web Remote Control system, for sending commands to UE4 remotely via the HTTP protocol.

The nDisplay system, for output to room-scale installations, gets support for curved and spherical screens, and support for the Scalable Mesh Format and Multiple Projection Common Data Interchange standards.

Performance: beta support for virtual texturing and animation streaming
Other experimental features added in Unreal Engine 4.23 include new Streaming Virtual Texturing and Runtime Virtual Texturing systems, both intended to enable artists to use larger texture maps than would otherwise fit into GPU memory.

A separate animation streaming system is intended to improve performance when playing back animations, particularly long cinematics.

Asset creation: updated Material Editor, experimental support for Wacom tablets
Of the existing toolsets, artists working on asset development get workflow improvements in both the Material Editor and Material Instance Editor.

It is also now possible to to combine multiple shading models into a single material.

Another interesting addition is support for properties like pen tilt and pressure when using Wacom graphics tablets, which would open up new possibilities when modelling or texturing assets.

However, it’s currently a programmer-only feature, with a new plugin exposing the relevant parameters to custom tools: none of UE4’s native tools yet natively support tilt or pen pressure.

Lighting and rendering: new system for HDRI backdrops, updates to RTX ray tracing
Lighting changes include a new HDR Backdrop actor, intended to streamline the process of setting up HDR environments for product visualisation.

There are also workflow improvements in Unreal Engine’s handling of IES profiles, for using real-world lighting data in architectural visualisations, primarily to the way IES lights are previewed.

For real-time work, Unreal Engine 4.23 adds a new Slope Bias parameter, intended to reduce visual artefacts when using dynamic shadows.

In the rendering toolsets, the experimental Nvidia-RTX-hardware-accelerated ray tracing system added in Unreal Engine 4.22 has been updated.

The changes are largely stability and performance improvements, but also extend ray tracing support to a range of new geometry and material types, including Landscape Terrain.

Under the hood, Unreal Engine’s renderer is being ported to the Render Dependency Graph (RDG), a new graph-based scheduling system designed to take advantage of modern graphics APIs like DirectX 12.

Layout: updates to landscape editing, foliage and environment fog
Unreal Engine 4.23 also adds a number of new features to the game engine’s environment toolset, including non-destructive layer-based editing for heightmaps and paint layers.

Other new environment features include the option to place interactive actors as well as static meshes with the Foliage tool, new control parameters for environment fog, and improved workflow for landscape splines.

Animation: new Dynamic Animation Graphs, updates to the Sequencer cinematic editor
Animation changes include Dynamic Animation Graphs, an experimental new animation-layer-controlled system for switching between subsections of an animation graph.

The feature is intended to enable multiple artists to work on an animation simultaneously.

Sequencer, Unreal Engine’s cinematic editor, gets a number of changes to the built-in curve editor, including new key retiming and transformation tools.

Developers get the option to add toolbar buttons, tool modes and data filtering types to the curve editor without having to modify the engine code.

File export: ProRes export, Python-scriptable FBX animations
VFX artists get the option to export footage in Apple’s ProRes format, with support for all of the ProRes codecs and embedded timecode, although not currently embedded audio.

ProRes export is currently supported on Windows only.

In addition, Unreal Engine’s media framework can play back files encoded using the HAP codecs. The system currently doesn’t support 8K or 16K footage, or embedded timecode or audio.

Users can also now control the export of animations in FBX format via Python scripting.

Other features: Unreal Insights analytics system, new audio tools, support for HoloLens 2
Non-artist-focused features include Unreal Insights, a new beta toolset designed to enable developers to collect data about Unreal Engine’s behaviour and performance during live sessions.

A separate command-line tool, CSVToSVG, plots raw data in CSV format as graphs in SVG format, making it easier to visualise the information collected.

Audio artists get Wavetable Synthesis, a new monophonic wavetable synthesis plugin; plus support for the Open Sound Control (OSC) standard.

There are also the usual range of performance improvements and platform updates, including beta support for Microsoft’s upcoming HoloLens 2 mixed reality headsets.

Pricing and system requirements
Unreal Engine 4.23 is available for 64-bit Windows 10, macOS 10.14 or Linux. Use of the editor is free, but Epic takes 5% of gross beyond the first $3,000 per quarter for any product you release commercially.

Read an overview of the new features in Unreal Engine 4.23 on Epic Games’ blog