Eye Tracking in Unreal Engine¶

Status: emerging
Last updated: 2026-05-31
Sources: Unreal Eye Tracking Sdk Overview, Sranipal Framework Overview, Godot Openxr Eye Gaze Interaction Extension
Tags: [unreal-engine, eye-tracking, openxr, sranipal, vive, varjo, meta, ue5]

Summary¶

Unreal Engine 5 ships a built-in OpenXR eye-tracking plugin and supports several vendor SDKs, giving it eye-tracking coverage close to Unity's. UE5's OpenXREyeTracker plugin implements XR_EXT_eye_gaze_interaction and, depending on runtime, can surface per-eye as well as combined gaze through the IEyeTrackerModule interface (Anonymous, 2026). Richer data comes from the VIVE OpenXR plugin (XR_HTC_eye_tracker), the Varjo Unreal plugin, and the Meta XR plugin, while HTC SRanipal is UE4-only and Tobii has no Unreal SDK (Anonymous, 2026). UE5 is effectively free for non-commercial research; a 5% royalty applies only to commercial revenue above $1M.

Body¶

Context¶

This article combines three sources on Unreal Engine's eye-tracking options: an unverified web-search digest of Unreal eye-tracking SDKs and plugins (Anonymous, 2026), HTC's SRanipal framework overview (HTC Corporation, 2026), and the OpenXR XR_EXT_eye_gaze_interaction specification (Khronos Group, 2026). They are technical feature digests describing UE5's built-in OpenXR plugin, the vendor SDKs around it, the dead ends, and licensing. Within this knowledge base this is the Unreal arm of the per-engine eye-tracking survey: it inherits the shared baseline in Openxr Eye Gaze Interaction, leans on the dedicated Sranipal Sdk article for the HTC path, runs parallel to Unity Eye Tracking and Godot Eye Tracking, and feeds the cross-engine ranking in Eye Tracking Engine Comparison, which places Unreal close behind Unity. Each point below is attributed to its source.

Key Points¶

Unreal's native path goes slightly beyond the bare OpenXR floor. Anonymous (2026) report that UE5 (5.0–5.4+) ships a built-in OpenXREyeTracker plugin implementing XR_EXT_eye_gaze_interaction, accessible from Blueprint (the Get Eye Gaze Data node) and C++ (the IEyeTrackerModule interface and FEyeTrackerGazeData), exposing combined gaze position and orientation, per-eye gaze, a fixation point in world space, and gaze confidence. Per-eye availability depends on OpenXR runtime support, and the standard interface still provides no pupil, blink, or high-frequency raw data (§ 1. Unreal Native OpenXR — OpenXREyeTracker Plugin). This is marginally richer than Unity's native combined-gaze-only exposure but rests on the same Khronos Group (2026) standard described in Openxr Eye Gaze Interaction.

HTC support splits along the engine-version boundary, the defining Unreal constraint for Vive hardware. Anonymous (2026) note that SRanipal's Unreal plugin supports only up to UE4.27 with no official UE5 build and only mixed community compile attempts; it exposes combined and per-eye gaze, normalized pupil, normalized openness, and blink at 120 Hz (§ 2. HTC SRanipal SDK in Unreal Engine). For UE5, HTC's recommended path is the VIVE OpenXR plugin (UE5.0+) using the vendor extension XR_HTC_eye_tracker, which adds per-eye gaze rays, normalized pupil size, eye openness, and per-eye gaze validity on top of the standard extension, integrated through the standard IEyeTrackerModule and Blueprint-accessible (§ 3. HTC VIVE OpenXR Plugin in UE5). VRCFaceTracking Project (2026) frame the same UE4-to-UE5 SRanipal gap and the OpenXR pupil-data trade-off set out in Sranipal Sdk (§ Migration Recommendation (HTC Official)).

The remaining vendor SDKs mirror their Unity counterparts with notable exposure gaps (Anonymous, 2026). The Varjo Unreal plugin (v4.x, UE5.0–5.4+, free with hardware) exposes combined and per-eye gaze, gaze origin, focus distance, openness, per-eye validity, and a stability class (fixation, saccade, etc.) through a Blueprint function library, but its calibrated millimetre pupil and iris exposure is more limited than the Unity plugin's — some metrics require direct C++ API access rather than Blueprint nodes (§ 4. Varjo Unreal Plugin). The Meta XR plugin (v69+) provides per-eye gaze direction, gaze origin, and per-eye confidence through the Get Eye Gaze State Blueprint node on Quest Pro, with the same limits as Unity: no pupil or blink through the standard API, and eye openness only via the separate Body Tracking/Face Expressions API (§ 5. Meta XR SDK in Unreal — Quest Pro Eye Tracking).

Two paths are dead ends (Anonymous, 2026). There is no Tobii XR SDK for Unreal — Tobii Ocumen is Unity-only and the screen-based Tobii Pro SDK has no UE binding, leaving a UDP bridge as the only option (§ 6. Tobii in Unreal). The HP Reverb G2 Omnicept had a UE eye-tracking plugin, but HP discontinued the Omnicept platform in 2023, and Windows Mixed Reality support was removed from Windows 11 in October 2024, so it offers no viable path forward (§ 7. HP Reverb G2 Omnicept).

Licensing leaves eye tracking unrestricted and favours research (Anonymous, 2026). UE5 is free for non-commercial academic research with no revenue threshold and free for commercial products below $1M gross revenue; a 5% royalty applies only above $1M, a custom no-royalty enterprise license is available, and Epic MegaGrants ($5K–$500K, reviewed twice yearly) are open to XR research. No UE5 eye-tracking feature is tier-restricted (§ 8. Unreal Engine Licensing Summary).

Conclusion¶

Read together, the sources place Unreal close to Unity: UE5's built-in OpenXR plugin reaches slightly past the bare floor (Khronos Group, 2026; Anonymous, 2026), and vendor SDKs add per-eye and (on Vive) normalized pupil data, while licensing strongly favours research. The gaps are specific — no UE5 SRanipal and the pupil-data trade-off when moving to OpenXR (HTC Corporation, 2026), no Tobii Unreal SDK, more of Varjo's calibrated-mm metrics locked behind C++ rather than Blueprint, and the discontinued Omnicept path (Anonymous, 2026). The cross-engine cost and capability trade-offs are compared in Eye Tracking Engine Comparison.

References¶

Anonymous (2026) Eye Tracking in Unreal Engine — SDK and Plugin Overview (Web Search Digest). Research digest, virtual-environments-kb RAW (Accessed: 31 May 2026). unrealEyeTrackingOverview2026

VRCFaceTracking Project (2026) SRanipal — VIVE Hardware Documentation. VRCFaceTracking Docs. Available at: https://docs.vrcft.io/docs/v4.0/hardware/VIVE/sranipal (Accessed: 1 June 2026). vrcftSranipal2026

Khronos Group (2026) XR_EXT_eye_gaze_interaction — OpenXR Specification. Available at: https://registry.khronos.org/OpenXR/specs/1.0/html/xrspec.html#XR_EXT_eye_gaze_interaction (Accessed: 31 May 2026). khronos2026eyegaze

Open Questions¶

How much of Varjo's calibrated mm pupil/iris data is reachable from Blueprint versus C++ in the Unreal plugin? The digest says "more limited" without enumerating which metrics (Anonymous, 2026).
Does the UE5 OpenXREyeTracker per-eye gaze work across runtimes, or only specific ones?