Platforms and systems

Spectral's features have different requirements. Creating a bake is an editor operation. Playing back baked lighting can work on a less demanding configuration, without runtime ray tracing.

Compatibility is split into shader model, graphics API, renderer, and view mode. These are separate choices, so you can see which setting prevents a feature from working without reading a long combined configuration name.

Before choosing Spectral for a projectWarning

These tables describe feature requirements, not a list of certified devices. Check the setup requirements below and test your packaged game on the intended hardware. An editor preview is not a mobile or headset performance test. Android's desktop renderer is discussed separately below; desktop Vulkan support does not automatically establish Android support.

Feature compatibility matrix

Read one row from each group. Yes means that choice is supported subject to the API-specific requirements below. No means that choice rules the feature out. Every applicable row must say Yes; one Yes does not override a No in another group. The project and hardware requirements below still apply.

For example, SM5 blocks bake creation regardless of the graphics API. DirectX 11 also blocks creation. Neither restriction prevents playback of finished lightmaps or probe lighting. Likewise, SM6 does not make GTAO work with the forward renderer.

Static bake: create describes the supported authoring setup, not the game's runtime target. Scroll sideways to see every feature; the setting column stays visible.

Shader model

SM5 and SM6 below describe desktop shader paths. ES3.1 uses the mobile renderer listed in the Renderer group.

Shader model	Static bake: create	Static lightmaps: playback	Probe surface GI	Baked static shadows	GTAO	PCSS	Tonemappers	Probe fog lighting	Probe capsule lighting
SM5	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
SM6	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes

Graphics API

These API rows describe desktop rendering. Vulkan support for baked shadows, PCSS, and probe fog lighting includes the latest Spectral changes. It does not change the separate bake-creation requirements.

Vulkan shadows require SM6Info

For Baked static shadows and PCSS, Vulkan requires SM6. DirectX supports these features on SM5 or SM6. A Yes in both the SM5 and Vulkan rows does not mean that the combined Vulkan SM5 shadow path is supported. This extra restriction does not apply to ordinary static lightmap or probe-surface playback.

Graphics API	Static bake: create	Static lightmaps: playback	Probe surface GI	Baked static shadows	GTAO	PCSS	Tonemappers	Probe fog lighting	Probe capsule lighting
DirectX 11	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
DirectX 12	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Vulkan	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes

Renderer

The mobile row covers the standard mobile renderer, including ES3.1 and standalone mobile VR. Android's optional desktop renderer has separate limitations explained below.

Renderer	Static bake: create	Static lightmaps: playback	Probe surface GI	Baked static shadows	GTAO	PCSS	Tonemappers	Probe fog lighting	Probe capsule lighting
Desktop deferred	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Desktop forward	No	Yes	Yes	No	No	No	Yes	No	No
Mobile	No	Yes	Yes	No	No	No	No	No	No

View mode and VR

Mono means a normal single-view render. Stereo includes headset rendering and instanced stereo. For VR, also check whether the project uses desktop forward, desktop deferred, or the mobile renderer.

View mode	Static bake: create	Static lightmaps: playback	Probe surface GI	Baked static shadows	GTAO	PCSS	Tonemappers	Probe fog lighting	Probe capsule lighting
Mono	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Stereo / VR	No	Yes	Yes	No	No	No	No	No	No

The stereo PCSS entry is No for the supported Spectral feature set. Stereo excludes the baked-shadow branch; compatibility of the separate native PCSS path in VR has not been established here.

An unavailable Spectral feature does not mean Unreal has no equivalent. Native AO, tonemapping, shadows, or fog may still work under Unreal's own renderer requirements. The Tonemappers column refers to Spectral's selectable transforms, not Unreal's ability to tonemap a mobile image.

Baking and lightmap playback

Create a static bake: use Windows · DirectX 12 · SM6 · deferred · mono in the editor, with hardware ray tracing, path tracing, static lighting, and the required project settings enabled. This is the supported authoring setup listed as Yes. SM6 alone is not sufficient. A runtime target does not need to run the baker.

Play back static lightmaps: baked textures use Unreal's lightmap rendering path. Keep static lighting enabled and cook the lightmap formats needed by the target. Mobile lightmap playback is separate from probe GI and Spectral baked static shadows. A working lightmap does not establish support for either of those.

Static lightmap playback is supported across the desktop, Vulkan, mobile, and VR configurations listed above. These are normal setup requirements, not a Vulkan-specific compatibility limitation. Epic lists precomputed lighting for both mobile rendering and the forward renderer used for VR.

For SM5, DirectX 11, forward, mobile, or VR targets, create the lighting using the authoring setup above, then switch to the intended runtime configuration and test the finished data. No in the creation column does not prevent lightmap or probe playback on those targets.

Vulkan and bake creationNote

Spectral blocks lighting bake creation while the editor is running Vulkan. For a Vulkan project, restart the Windows editor with -dx12, using the required DX12/SM6 baking configuration, then bake and save the level and lighting data. Restart using Vulkan to render and test the result. Vulkan playback support does not enable Vulkan baking.

Probe surface lighting

Static Sky Light for mobileWarning

For Spectral's mobile baked-lighting workflow, set the Sky Light's Mobility to Static before baking. Changing mobility alone does not rebuild the lighting. See Sky Light on mobile for setup and target checks.

A Spectral Probe Volume needs valid baked data, coverage around the receiver, shader hooks, GPUScene, and support for its volume-texture resources. Sampling the field does not need runtime ray tracing.

The surface-lighting implementation has no Direct3D-only, deferred-only, or non-stereo restriction. It has desktop SM5-or-higher and mobile shader hooks, which is why the listed desktop, Vulkan, forward, mobile, and VR paths are marked Yes. This does not mean every device can hold an arbitrarily large field: texture-format support, texture limits, GPUScene, and the target's supported material permutations still apply.

The mobile ES3.1 hook is separate from the desktop implementation. Enable Support GPUScene on Mobile and restart before testing. Without it, the mobile base pass cannot access the scene's probe data and the contribution is skipped. Supported material and vertex-factory permutations also matter: the mobile hook is not an extra probe layer over every lightmapped mobile material.

Mobile SM5 is not the normal mobile renderer. Android Vulkan using the desktop renderer must pass the desktop shader-platform checks used by individual effects. Static lightmaps and probe surface GI are supported, but support for baked static shadows, GTAO, PCSS, tonemappers, probe fog lighting, and probe capsule lighting on this Android path has not been established. Do not infer support from the desktop Vulkan row. Confirm these integrations before choosing Android's desktop renderer for a project.

Shadows and screen-space effects

• Baked static shadows: supports desktop DirectX 11 and DirectX 12 on SM5 or higher, and desktop Vulkan on SM6. Deferred shading and a non-stereo view are required. This is separate from ordinary static lightmap playback.
• GTAO: requires desktop deferred, non-stereo rendering. Forward rendering, mobile shader platforms, and stereo views are excluded.
• PCSS: filters eligible conventional directional shadows, not Virtual Shadow Maps. Desktop DirectX 11 and DirectX 12 require SM5 or higher; desktop Vulkan requires SM6. Deferred shading is required. Mobile and forward shading are excluded. The baked branch also inherits the non-stereo baked-shadow restriction.
• Tonemappers: Spectral's selectable transforms require desktop SM5-or-higher, non-stereo views and the required floating-point texture support. Native Unreal tonemapping remains separate.

Probe-lit fog and capsules

Both integrations require desktop SM5-or-higher deferred, non-stereo rendering, static lighting, and valid probe data. They exclude mobile shader platforms, forward rendering, and stereo views.

Probe fog lighting supports desktop Vulkan as well as DirectX 11 and DirectX 12. Choosing Vulkan does not remove the renderer, view-mode, or valid-probe-data requirements.

Probe fog lighting supports both Spectral Fog Volume and Unreal's Exponential Height Fog with Volumetric Fog enabled. It lights the volumetric medium, not the separate non-volumetric height-fog approximation. See Fog.

Probe capsule lighting also needs a character already configured for Unreal's indirect capsule shadows. The integration preserves an existing native volumetric lightmap: if one is registered in the world, the auxiliary probe bridge is not installed.

Engine installation and target validation

These docs describe Spectral across supported Unreal Engine versions. Precompiled modules must still match the installed engine, and shader hooks must match its shader sources. This is an installation compatibility requirement, not a different documentation workflow for each package.

Test a cooked build using the intended API, renderer, device profile, scalability, and, for VR, both eyes. Check each feature independently. Unlisted platforms, including console and Metal targets, have no support claim in this matrix; confirm them before purchase.

For engine-side context, see Epic's mobile rendering guidelines and Volumetric Fog reference. They do not override Spectral's restrictions above.