Developing VR Interaction Mechanics for Games

We are a team of game dev engineers with 12 years of VR development experience. We have delivered over 30 projects for various platforms. Moving controls from a flat screen to VR means starting from scratch. Familiar patterns (action button, cursor, grid inventory) in virtual reality are either inconvenient, cause motion sickness, or break immersion. Good VR interaction mechanics should be obvious without a tutorial: the user reaches out and grabs an object because that is how the physical world works.

Why Grab Mechanics Fail Most Often

Object interaction is the core mechanic of most VR games, and this is where things go wrong most often. Problem number one: penetration through colliders. When a player physically reaches for an object, their hand-controller may pass through a table, wall, or the object itself. A physical collider on the hand with isKinematic = false solves this but creates another issue: the hand starts jerking when contacting surfaces due to conflict between tracking positioning and the physics engine.

The working solution we use in XR Interaction Toolkit (https://learn.microsoft.com/en-us/unity/) is to separate the visual hand (follows tracking without physics) and the physics hand (Rigidbody with collider, follows tracking position via joint). When trying to pass through an object, the physics hand stops, the visual hand continues moving—and a small discrepancy (up to 5–8 cm) remains imperceptible thanks to haptic feedback triggered at the moment of contact. This is called the phantom hand approach, and it is 2× more effective than naive hand collision in reducing clipping issues.

The second common mistake is incorrect attachment point when picking up an object. If the object snaps to the hand bone position without considering orientation, the player sees the object sticking out of the palm at an unnatural angle. In XR Interaction Toolkit, this is solved via Attach Transform on each XRGrabInteractable: a separate empty object with the correct position and rotation relative to the item, indicating exactly how the object rests in the hand.

How to Ensure Comfortable VR Locomotion?

VR locomotion is the second most challenging task in VR. Smooth stick movement causes motion sickness in a significant portion of the audience. Teleportation is safe but breaks immersion in some genres. The solution is usually hybrid.

XR Interaction Toolkit provides ready components: TeleportationProvider, SnapTurnProvider, ContinuousMoveProvider. But out of the box, they require tuning for a specific game. For shooters, smooth locomotion with vignette (peripheral darkening during movement) is usually needed—this reduces motion sickness by 40–60% according to Oculus Research. We expose the vignette intensity parameter in Comfort Settings so the player can disable it if desired.

For spatial puzzles and horror games, VR teleportation works better—it preserves tension and does not cause discomfort. Implementation uses TeleportationArea and TeleportationAnchor components, with arc visualization via XRInteractorLineVisual and TeleportationProvider on the Locomotion System.

Approach comparison: teleportation gives no motion sickness but medium immersion, smooth + vignette gives high immersion with 2.5× less motion sickness than smooth without vignette, and room-scale walking gives absolute immersion with no sickness. Teleportation is recommended for puzzles, horror, quests; smooth with vignette for shooters and simulators; room-scale for small-world action games.

An important nuance: if the player can physically walk around the room, you must account for their physical position within the Guardian/Boundary area affecting in-game position. When implementing mechanics that require precise positioning (e.g., pressing a button at a specific spot within 5 cm accuracy), you need to check not only the world coordinates of the controller but also its relative position to the camera.

What's Included in Turnkey VR Mechanics Development?

We provide a full cycle: from prototyping to integration on target platforms (SteamVR, Oculus Quest, Android XR). Each stage is accompanied by documentation and code review. Our turnkey development starts at $5,000 for basic grab and teleportation, and clients typically save 30% compared to building in-house.

1. Requirements analysis: identify key mechanics, platforms, constraints (e.g., FPS budget of 72 FPS on Quest, room-scale, supported controllers).
2. Prototyping: fast MVP in Unity with XR Device Simulator—without a headset—to test interaction hypotheses.
3. Implementation: write core mechanics including VR grab, VR locomotion, UI in virtual reality, and VR haptic feedback. Use XR Interaction Toolkit, custom shaders, and animations.
4. Testing: real headset tests with a group of 10+ users with varying motion sickness tolerance. Fix penetrations, non-intuitive grabs, and kinematic errors. We measure success by a 90% reduction in motion sickness complaints.
5. Documentation: diagrams of Attach Transforms, haptic settings, rules for game designers.
6. Deployment and support: build configuration for each platform, optimization of draw calls and asset streaming, source code and instructions handover.

Estimated timeline: basic VR grab + locomotion (teleportation) takes 1–2 weeks; physics grab + two-handed VR interaction takes 2–4 weeks; full mechanics set (grab + UI + locomotion + haptics) takes 4–8 weeks; custom physics interaction system takes 6–12 weeks.

Pro tip: For testing, use at least 10 people with different motion sickness tolerance levels to ensure robust results.

What Are Non-Standard Mechanics and How to Implement Them?

Two-handed VR interaction: holding a long weapon with both hands requires TwoHandedGrab with correct object orientation calculation using two attachment points. In XR Interaction Toolkit, this is implemented via TwoHandInteractionAffordance or a custom XRGrabInteractable with an overridden CalculateInteractorPosition.

VR haptic feedback as an information channel: controller vibration is not just tactility—it's feedback. Different intensity and patterns (short pulse vs. rising vibration) convey different states: picking up a light object vs. heavy, contact with a hot surface vs. cold. Through XRBaseController.SendHapticImpulse(amplitude, duration) this is implemented in a few lines, but the game designer must specify concrete parameters for each case.

UI in virtual reality: standard Canvas in Worldspace mode, interaction via XRUIInputModule instead of the standard StandaloneInputModule. Laser pointer from the controller via XRRayInteractor. The main rule: UI should be in a physically reachable zone or interacted with via ray, but must not require precision smaller than 1–2 cm—controller tracking with an extended arm has an error of up to 5–10 mm, making small buttons a pain.

Contact us to evaluate your project. We guarantee immersion and no motion sickness. Request a consultation and get a detailed development plan.

VR and AR Development

When we first launch a project in a VR headset, most teams face the same thing: technically everything works, but in the headset either motion sickness occurs, or hands 'float' with a delay, or the scene looks jerky at the periphery. These are not bugs in the usual sense — they are a consequence of the fact that VR/AR development requires a different approach to render architecture, interaction, and UX from the very beginning of the project. Our experience: over 7 years in game dev, 15+ completed VR/AR projects for Meta Quest, SteamVR, PSVR2, HoloLens. We work with teams that need not just a prototype but a production‑ready application with a stable frame rate.

Platforms and SDKs

We work with all relevant stacks. We use OpenXR as the base layer wherever possible — it provides cross‑platform compatibility between Meta, Valve Index, HP Reverb and other PC VR devices. On top of OpenXR, we build on the XR Interaction Toolkit (Unity) or VR Expansion Plugin (Unreal). Contact us for a stack assessment tailored to your project.

How to minimize motion sickness in VR locomotion?

Locomotion — the main source of motion sickness for inexperienced VR users. According to research, about 70% of users experience discomfort with improper movement settings Oculus Developer Guidelines. Teleportation — standard navigation method when smooth movement is undesirable.

Components from XR Interaction Toolkit: TeleportationArea, TeleportationAnchor, TeleportationProvider. Basic implementation works out of the box, but for production we refine it in four steps:

1. Setting up XRRayInteractor with a curved ray (Bend Ray) — the teleportation arc looks more natural than a straight ray and is perceived better by users.
2. Adding a valid landing zone — a visual indicator changes color when hovering over an obstacle (red/green).
3. Implementing fade transition — smooth screen fade (black fade) before teleportation reduces disorientation.
4. Rotation snapping — after teleportation we offer snap rotation by 45° or 90° instead of smooth, reducing motion sickness risk.

For projects requiring smooth locomotion (action games, simulators), we use comfort settings: vignetting during movement, reducing FOV during acceleration. Settings are available to the user in the menu — different people have different sensitivity thresholds. The difference between kinematic and physics‑based movement: kinematic gives instant hand following but lets objects pass through walls; physics‑based via Joint provides realistic collisions but requires velocity damping and max joint force tuning. We choose based on the type of interaction.

How to make object grabbing in VR physically realistic?

This is the most underestimated part of VR development. Clients often perceive it as 'just hand animation', but in practice it is a complex system where physical correctness, responsiveness, and comfort conflict.

Grab (grabbing)

XR Interaction Toolkit provides three types of Interactable for grabbing:

• XRGrabInteractable — standard grab, object follows controller via physics joint or direct position/rotation
• XRSimpleInteractable — for objects without physical movement (buttons, levers)
• Custom Interactable by inheriting from XRBaseInteractable

Attach Transform — a frequently ignored detail. Each Interactable must have a properly configured Attach Transform (the point where the hand 'attaches'). Without it, the pistol grip will be at the center of the mesh, not where it is held.

For weapons and tools with two‑handed grab — a separate TwoHandGrab system: leading hand determines position, the second — orientation. XR Interaction Toolkit supports this via XRTwoHandGrabInteractable or custom logic with two Attach Points.

Throw (throwing)

Velocity smoothing is critical for realistic throwing because the Rigidbody.velocity at the moment of controller release reflects instantaneous speed, often incorrect due to tracking discretization. The user makes a quick wrist movement — but the object flies half as fast.

Solution: velocity smoothing over the last N frames (typically 5–10 frames, ~80–160 ms at 60 Hz) before release. XR Interaction Toolkit does this via VelocityEstimator. Additionally, we apply a velocity scaling multiplier — a small speed increase (1.2–1.5×) makes throws subjectively more satisfying. Angular velocity (for objects that should spin in flight) is also averaged similarly.

AR: Plane Tracking and Environment Interaction

AR adds a different class of problems — working with real, unpredictable environment. AR Foundation — a cross‑platform layer on top of ARKit and ARCore. Most basic features (plane detection, raycasting, image tracking, face tracking) are available through a unified API.

Plane Detection

ARPlaneManager detects horizontal and vertical planes. Practical nuances:

• Initialization takes time — the user must look around the room while the system builds a map. An explicit onboarding with instruction 'slowly move the camera across surfaces' is needed.
• Planes are unstable — their boundaries and position are updated as data accumulates. Objects placed on a plane need to be attached via parent to ARPlane, not to world coordinates.
• Plane merging — two detected floor segments may merge into one, moving the anchor. For critical anchors, use ARAnchor instead of direct attachment to the plane.

Image tracking (via ARTrackedImageManager) quality directly depends on the quality of reference images. Images with high detail frequency and contrasting edges (like a QR code but stylish) track more reliably than smooth logos. ARCore Geospatial API — for outdoor AR with real‑world coordinate binding (accuracy up to 10 cm in well‑mapped areas).

Optimization for VR: Frame Rate and Comfort

VR requires stable high frame rate. About 60% of development time in mobile VR goes to optimization, not functionality — retrofit costs twice as much as proper architecture from the first sprint.

Single Pass Instanced Rendering

The main render optimization in VR. Without it, the scene is rendered twice (once per eye), doubling draw calls. Single Pass Instanced renders both eyes in one pass via instancing: geometry is processed once, the shader gets two view/projection matrices through GPU instancing. Enabled in Unity via XR Plug-in Management > Rendering Mode: Single Pass Instanced. Important: custom shaders must support SPI — standard URP/HDRP shaders support it, custom HLSL requires modifications (UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX and related macros). Applying this technique reduces draw calls by 40–50%, making it twice as efficient as naive double rendering.

Foveated Rendering

On Meta Quest, Fixed Foveated Rendering (FFR) is available — reducing resolution at the periphery where visual acuity is lower. Configured via OVRManager or Meta XR SDK:

OVRManager.fixedFoveatedRenderingLevel = OVRManager.FixedFoveatedRenderingLevel.High;
OVRManager.useDynamicFixedFoveatedRendering = true;

Dynamic FFR automatically increases the level when frame rate drops — more convenient than fixed in scenes with variable load.

IPD and Comfort Settings

IPD (Inter‑Pupillary Distance) — affects depth perception. At the programmable level on most devices, only reading IPD is available (OVRPlugin.GetSystemDisplayFrequency), physical adjustment is on the headset. For applications requiring precise positioning (medical simulators, training), we account for IPD in scene scale calculations.

Haptics

Haptic feedback — an underestimated tool. Even a simple vibration response when grabbing an object or hitting significantly increases the sense of presence. On average, integrating haptic patterns takes 30–80 hours per project.

XR Haptics via OpenXR:

var hapticImpulse = new UnityEngine.XR.HapticCapabilities();
InputDevice device = InputDevices.GetDeviceAtXRNode(XRNode.RightHand);
device.SendHapticImpulse(0, amplitude: 0.5f, duration: 0.1f);

For complex patterns (tactile 'texture' of a surface when touched, increasing vibration when drawing a bowstring) we use Meta Haptics Studio — allows designing haptic clips visually. This can reduce time spent on manual haptic tuning by about 30%.

What does VR/AR application development include?

When ordering a turnkey project, we provide the following deliverables:

• Architectural document with stack description, render logic, and interaction system
• Working prototype (MVP) for testing on target device
• Integration of necessary SDKs (Meta XR, OpenXR, AR Foundation, etc.)
• Optimization for target frequencies 72/90/120 Hz with draw call and FPS profiling
• Testing on physical hardware (Quest, SteamVR, HoloLens) with user involvement
• Full documentation for build, deployment, and support
• Training for the client's team (workshop on XR Toolkit)
• Warranty support for 1 month after delivery

What affects cost and timeline?

VR/AR projects are more expensive than regular games of similar scope. Iterations are slower — each fix must be tested in the headset, an emulator does not convey the real experience. Motion sickness forces reworking some conceptual decisions after the first playtest. Optimization takes a significant portion of time — for mobile VR (Quest) up to 60–70% of the cycle. For Quest projects, we start optimization from the first sprint. The cost of basic SDK integration (XR Interaction Toolkit) varies depending on the scope of custom Interactable. Typical budgets for a full Quest project range from $25,000 to $80,000 depending on complexity, number of custom interactions, and depth of optimization. Proper architectural planning from sprint one typically saves 40% on later rework compared to fixing performance bottlenecks retroactively.

Get a consultation on your project — we will assess the task, stack, and timelines. Order turnkey VR/AR application development with a guaranteed stable frame rate.