Unreal Engine 4.18 Preview


A Preview of the upcoming 4.18 release is available now on the Launcher and Github. We have made this Preview available so that our developer-community can help us catch issues before the final release. As fixes are implemented, we will release updated previews throughout the development cycle. Please be aware that the preview releases are not fully quality tested, that they are still under heavy active development, and that they should be considered as unstable until the final release. Developers should not convert their projects for active development on preview releases. Please test on copies of your project instead.

We encourage users to check out the preview to try new features and inform us of any issues which we may not have caught. Links to known and fixed issues for this release are provided below. If you discover any additional issues with this preview release, please report them using the guidelines in the link: How to Report a Bug.

Known & Fixed Issues

4.18 Preview Summary

This list provides a brief summary of updates in this Preview which may benefit from additional testing. Not all updates may be listed. Full release notes will be made available with the final 4.18 release. We may not be able to provide additional information about updates at this time.

  • VR/AR Updates:

  • Unified Apple ARKit and Google ARCore Initial Support


  • We’ve released the first portion of our unification of the base functionality between Apple’s ARKit and Google’s ARCore developer preview. We’ll continue to grow and mature these APIs, but in the beginning, passthrough cameras and camera control and synching have been unified, and are built on top of our new shared XR engine layer.
  • Important: ARKit requires an iOS device with an A9 or later processor. (see Apple documentation)
  • To make your app available only on devices supporting ARKit, use the arkit key in the UIRequiredDeviceCapabilities section of your app’s Info.plist. If augmented reality is a secondary feature of your app, use the isSupported property to determine whether the current device supports the session configuration you want to use.

Unified XR Engine Layer

  • We’ve created a shared XR layer in the engine to support VR and AR Systems so that all existing system plugins now build upon the default camera implementation for both Camera Components and camera passthrough view. This not only makes behavior more consistent between VR and AR platforms, but should help simplify hardware developers adding support for their platforms to UE4.

Rendering Updates:

  • Volumetric Lightmaps are the new default (WorldSettings -> Lightmass) and take effect after building lighting. They give higher quality indirect lighting for movable objects, and higher quality indirect lighting for volumetric fog, particles, and instanced meshes.

  • New settings under WorldSettings -> Lightmass


  • Volumetric Lightmap Detail Cell Size: Size of the most detailed cells, in world units. Smaller cells increase memory and build times.

  • Volumetric Lightmap Maximum Brick Memory Mb: Provides an upper bound on memory used by Volumetric Lightmaps. Clamping memory too much results in inconsistent resolution.

  • Use Show -> Visualize -> Volumetric Lightmap to see the sample placement and lighting.

Precomputed Skylight improvements

  • Skylights are now represented to Lightmass using a filtered cubemap with a much higher default resolution. You can see the most difference in heavily occluded scenes.
  • There is now support for multiple skylight bounces through a new setting in World Settings -> Lightmass. Materials need to have a high diffuse value for multiple skylight bounces to be noticeable in most cases.

Mobile Updates:

  • iOS 11 is now supported

  • XCode 9 is now supported

  • (Experimental)** Desktop forward renderer on iOS. **The Desktop Forward Renderer, used in the Wingnut AR demo at WWDC 2017, is now available to all UE4 developers. This is recommended for iOS devices with an A10 or later processor running iOS 10.3 or newer. Forward Renderer documentation can be found here.

  • MSAA is not supported, please use TAA

  • Simplified iOS certificates and signing when using Remote Toolchain from PC. When using the remote toolchain to build iOS on a remote Mac from your PC, it’s no longer necessary to install your private key or certificates using Keychain Access on the remote Mac. The certificate and provisioning setup in from the Project Settings, iOS on the editor on your PC is all that is required.

  • Gradle is now the default for packaging Android APKs.

  • Ant is still available if necessary by disabling the “Enable Gradle” Android project setting, but it is recommended to transition to Gradle since Ant is considered depreciated.

  • If you previously did not accept the Android SDK license agreement by checking “Enable Gradle” in the previous version you will need to do so by clicking on the “Accept SDK License” button in Android project settings; an error will be shown if you try to package or launch on without doing so.

  • An Android Camera Plugin is available to expose access to the front and back cameras. Enabling the plugin adds a new Android Camera plugin project settings panel to select Android Manifest requirements.

  • International keyboards now work on the Android Virtual Keyboard

  • HTML5: Upgraded emscripten toolchain to 1.37.19 (from 1.37.9)

  • HTML5: Optimized browser WebAssembler (WASM) is now set to default. Massive improvements on asset sizes and browser load time and runtime performance.

  • The previous optimized HTML5 output ASM.js has been decommissioned and removed from the code base.

  • NOTE: multi-threading is not yet available on WASM, however, multi-threading is a major feature push for all browser makers in the next coming months.

**Media Framework Updates: **Please give this extra testing in the Preview!

  • Media Framework has been significantly updated and extended, and several media player plug-ins were largely rewritten in order to support upcoming advanced use cases, such as real-time video compositing, time synchronization, simplified workflows, capture hardware & video-over-IP support, online media streaming, integration with the Editor, and improved stability and performance. Parts of the API had to be redesigned in order to support these scenarios. Please note that some of this work, such as Sequencer integration, stereoscopic & 360 video support, and hardware accelerated 4K playback is still under active development.

  • Upgrade Notes - Content changes are required


  • MediaSoundWave assets were replaced with MediaSoundComponents

  • There is no automatic conversion (components require different workflow & user decisions)

  • Attach new MediaSoundComponents to Actors or UMG widgets

  • Existing MediaSoundWave assets must be deleted from Content directory on disk

  • MediaPlayer output settings were removed. Media assets now reference a MediaPlayer instead

  • MediaTexture and MediaSoundComponent have a setting for the Media Player to pull data from

  • MediaAssets module is now always loaded to prevent server-side BP problems

  • Material texture samplers now require the new Sampler Type “External”

  • MediaOverlay assets were removed as a concept

Moved high-level media player logic into reusable Engine-agnostic classes
For audio, a new media sample rate converter that supports:

  • int8, int16, int32, float, double input samples
  • any sample rate, including variable rates
  • up to 8 audio input channels
  • 1 and 2 output channels

In the Media Player Editor, new track format selector menu, audio/video capture device selector, and and playlist controls.
New Blueprint functions for querying media player tracks and formats, and blueprint function library for enumerating audio, video, and webcam capture devices
Media Framework plug-in for Android webcam support
And much more!
Animation/Physics Updates:

  • Clothing Tools improvements are no longer ‘experimental’.

  • New tool panel available in the Skeletal Mesh Editor for editing clothing data.

  • Simple to create clothing data in the Skeletal Mesh Editor by right clicking the mesh section to convert

  • Per vertex clothing parameters (Max Distance, Backstops) paintable in-editor

  • Multiple paint tools available: Brush, Gradient, Smooth, Fill

  • Integrated with physics assets for collision authoring.

  • Expanded list of configuration parameters. Painted parameters can be switched out instead of overwriting to aid iteration.

  • New LOD pipeline for creating and replacing simulation meshes in a Clothing Data object

  • The Physics Asset Editor has a new look and feel, with many improvements such as a new graph view showing constraints between bodies, an updated tree view with better filtering, improvements to animation playback and simulation, and more.

  • Additionally, Physics assets can now be created directly from the Content Browser.

  • The RigidBody Anim node has been improved by supporting a root bone simulation space option (useful when an attached Skeletal Mesh is counter-rotated from a player capsule), and by exposing inertia scaling and constraint dominance in the Physics Asset tool (which improves stability and jitter)

  • PhysicsAsset bodies can be auto-generated using multiple convex hulls per bone

  • The Blendspace Editor has improved discoverability by allowing the placement of an optional ‘Previewing Pin’ on the grid, and state-sensitive tips provided on the grid.

  • APEX Destruction has been moved into a Plugin, and is disabled by default.

Sequencer Updates:

  • Performance improvements including more efficient track, keyframe and path drawing

  • Various minor improvements:

  • Improvments to FBX import, including importing static/default transforms, adding cinematic cameras if corresponding one doesn’t exist, and an option to force font X axis.

  • More drag & drop support for shots

  • Added the ability to rerun construction scripts in editor while scrubbing.

  • Cine camera ‘Look at’ works with Roll

Audio Updates:

  • Attenuation Settings have been improved for clarity and organization.

  • Organized into categories with easier to read labels

  • New ability for Audio Plugins to indicate if they have custom settings, allowing certain Attenuation Settings to be concealed in the event the Audio Plugin replaces that particular feature.

  • Added Normalization option for 3D Stereo Sound Sources to prevent clipping when spread narrows into a single channel.

  • (New (Experimental) Unreal Audio Engine only) Cleaned up Reverb Send code and Added Support for multiple Reverb Send Methods: Linear, Custom Curve, Manual

  • (New (Experimental) Unreal Audio Engine only) Added option to apply a Distance Based High-Pass Filter to a Sound Source

  • (New (Experimental) Unreal Audio Engine only) Source Buses are a powerful new feature which allows multiple Sound Sources to send and sum into a single real-time Source. Source Buses are derived from Sound Base which allows them to be played and utilized in the same way Sound Waves or Sound Cues are employed.

  • (New (Experimental) Unreal Audio Engine only) Enhanced Audio Plugin architecture enabling a smoother integration for 3rd party developers wishing to override core mixing features.

  • Projects can mix and match plugins overriding Source Spacialization, Source Occlusion, and Reverb

  • Can now swap out different plugins without restarting the Editor!

  • (New (Experimental) Unreal Audio Engine only) New Submix Effects have been added to the Synthesis Plugin, allowing for complex and interesting enterative spatial effects.

  • (Experimental) The new Unreal Audio Engine now supports Nintendo Switch and HTML5 via SDL2.

Core Updates:

  • Visual Studio Code can now be used to write code on Windows, Mac, and Linux. To use it, select “Visual Studio Code” as your preferred IDE from the editor preferences dialog, or add the -vscode argument when generating project files on the command line.

Gameplay/Scripting Updates:

  • Cross-level Actor references are now better supported using Soft Object References, which were previously called Asset IDs/AssetPtrs. As part of this, the native types FStringAssetReference and TAssetPtr were renamed to FSoftObjectPath and TSoftObjectPtr. If you create a Soft Object Reference property pointing to an Actor, they now have an improved UI that will show rather they are unloaded or broken, as well as the full Actor ID they point to.

  • Cross level references like this will now correctly be fixed up if the referenced actor is renamed or moved using the “Move to current level” option. It will attempt to check out and resave any other levels/sequences that point to that specific actor. It will also warn you before deleting actors that are referenced in this way. They also now work correctly in PIE with level streaming. Newly created Sequencer actor references are now Soft Object References, but older Sequences will have to be fixed up with “Rebind Possessable References” and resaved first.

Tools Updates:

  • You can now preview your game localization in-editor

  • This is configured by the “Preview Game Culture” setting (“Editor Preferences” -> “Region & Language”), and will automatically be active when Play in Editor (PIE) is running. The preview language is also passed to any standalone games that are launched via the editor.

  • This preview can also be used in the UMG editor to preview widgets in different languages

  • While a preview is running, all editable text fields are locked-down (read-only) to prevent accidentally overwriting source data with translation data. You can also use this new lock-down feature to prevent any localization changes in your project (set “LockLocalization” to “True” under the “Internationalization” section of either your DefaultGame or DefaultEngine INI).

Console Updates:

  • New features and improvements are coming for development on XBox One, Nintendo Switch, and Playstation 4. Since console code is not available for the Previews, details will be provided with the final 4.18 release.


REMEMBER: Please report any new bugs you find by following the How To Report a Bug Guide.
If you experience a crash, please make sure to always submit the crash report along with a description of your actions at the time.

Desktop Rendering on iOS? SIGN ME UP.

This is awesome! Sucks you all couldn’t get 4.17.2 out this week. But the VR and Media framework stuff looks cool. If you can spoil us with more Gameplay/Editor Framework additions (if any), that would be awesome!

not alembic news?

I notice that the editor now scales with the Windows(10) DPI setting in 4.18. Making all editor elements appear to large on my setup(With 125% scaling).
Is this by design, or is this a bug ? I could not find a new setting to disable this.

Git Plugin Changeling for 4.18:

Bigger updates are coming for next version, and can be tested (backported to 4.17) by overriding the in-Engine plugin with the “dev” v2.2

My game looks very different on mobile - Very bright, very bloomed out :confused:


This is by design, but the lack of an option to disable it is not. That will be corrected by the time we release 4.18.0.

edit, from one of our engineers below:* “Putting -nohighdpi on the commandline when launching UE4Editor.exe will disable the DPI scaling.”*


Great to hear, thanks! :slight_smile:

This bug is still an issue with 4.18 preview, even when using the launcher version.

Putting -nohighdpi on the commandline when launching UE4Editor.exe will disable the DPI scaling.

Any updates on the new Geometry editing Tools would be awesome, when we could expect them to be released in an experimental state

Changing array values by dragging and dropping is really cool.

Awesome improvements, thank you! Looking forward to ARCore development, and I love the unified XR advancements. I predicted XR years ago, glad to see this is coming to fruition.
I have one question though: Where is Niagara?!?!?!?! Can we have any details? Cascade is the most dated part of the engine now and we haven’t heard a word about it in so long! We need that node based fx building :] Can’t wait for it

tldr; Niagara?! When??

When using Experimental/Enable Details Panel Favorites, all the FVector and USTRUCT UPROPERTYs are duplicated and scattered.

We are making a game with random generated levels on 4.17 where I have to fake indirect lighting with lightmaps
(we load sub levels as rooms).
Is possibile to move the level and the whole indirect lighitng after bake with the new lightmapping system?

Is it possible to launch ARkit apps directly from engine/windows to iOS test devices in 4.18 ? or do we need to build from a mac with xcode?

Can’t seem to find any of ARKit components, plugin is enabled. Missing ARKit camera component along with ARKit camera texture :s

Update: resolved below

Thanks for the update, upgraded my project because wanted to try the new wasm upgrades, fixed everything that changed and everything builds correctly, but if I run the project from visual studio, it stops at 45%, and if i try to run it from the .uproject, it stops at 53% every time. Anyone else experiencing this?

Project is massive and private so can’t upload, and no longer is being created (that i can see in my localdata or project folder).

Edit: After letting the .uproject sit loading for about 3 hours it finally loaded and seems to be much quicker each time. Still doesn’t seem to want to launch from visual studio though (DebugGame Editor config)

Edit 2: Also can’t build for html5 anymore (haven’t tried other builds yet), get NativizedAssets.Build.cs(5,14) : error CS0101: The namespace ‘<global namespace>’ already contains a definition for ‘NativizedAssets’

which I don’t understand at all, there is only one NativizedAssets.Build.cs, but there is a NativizedAssets.cpp file. I see no where else this is defined even searching the entire directory – not sure if this is 4.18 problem or just copy pasting the project, but it’s not happening on this project in 4.17

Please fix Unreal Engine Issues and Bug Tracker (UE-43093) in 4.18!!!