How We Optimize Custom VFX Particles for Mobile AR in Unity

Imagine launching an AR game with an explosion effect of 2000 particles. On iPhone 13 you get 45 FPS; on Adreno 618 just 22 FPS. Sound familiar? With 5+ years in mobile AR development (we've shipped over 50 AR projects for clients like gaming studios and enterprises), we know how to squeeze maximum performance from limited hardware. In this article, we'll break down why standard particle systems choke and how to fix it.

Why performance drops in AR particles

Overdraw is the main enemy on mobile GPUs. Each semi-transparent particle overlaps the previous one, forcing the GPU to perform blending for every overlap. 500 particles with Alpha Blend in Overlay mode means potentially 500 × (average overlap) blending operations per frame. On tile-based GPUs (Adreno, Mali), overdraw >3x in the effect area is a noticeable hit to GPU time.

Our solution: use Additive blending instead of Alpha Blend wherever possible. Additive doesn't read the destination buffer—it only writes addition, which is 2x faster. For fire, glow, and magical effects it's ideal. For smoke and realistic clouds, Additive looks unnatural, so we stick with Alpha Blend but limit particle count.

Collision with AR surfaces is expensive. Particle System → Collision → Type: World with Collision Quality: High forces every particle to perform a physical raycast each frame. 1000 particles with World Collision = 1000 raycasts/frame. On mobile, that's catastrophic.

Our approach: use Collision Type: Planes. We manually define several planes matching AR surfaces, updating them from ARPlane components in AR Foundation as new surfaces are detected. Not all physical details are captured, but performance improves by 10x.

Draw Calls from multiple renderers: Several Particle Systems with different materials create multiple Draw Calls that cannot be batched. GPU Instancing for Particle System is enabled via Material.enableInstancing = true, but works only for opaque or Additive particles—for Alpha Blend it's ineffective due to sorting requirements.

How we optimize particle systems for mobile AR games

Our step-by-step optimization plan:

1. Profile current effects to identify bottlenecks using Unity Profiler.
2. Choose blending strategy: replace Alpha Blend with Additive where possible.
3. Optimize collision: switch from World to Planes Collision.
4. Merge materials and enable GPU Instancing.
5. Profile on target devices and finalize tuning.

Visual Effect Graph (VFX Graph) computes particles on the GPU. Ideal for PC and consoles, but on mobile support is limited: requires Compute Shaders, available only on Metal (iOS A12+) and Vulkan (Android API 28+). Older devices won't handle it. If your target includes mid-range Android, VFX Graph is not suitable.

Burst Compiler + Job System for CPU particles: If particles are script-controlled (not standard Particle System), we move logic to IJobParallelFor with Burst. This yields 5–15x speedup over Mono, freeing the main thread.

LOD for particle systems via ParticleSystemRenderer.maxParticleSize and dynamic reduction of emission.rateOverTime based on distance to the AR object. At distances >3 meters from the AR marker, we halve particle count—visually imperceptible but reduces overdraw by 30%.

Texture Sheet Animation instead of multiple textures. One Sprite Sheet 512x512 with 16 animation frames replaces 16 separate textures—one Material, one texture sample, within a single Draw Call.

Real case: an AR iOS game with magic effects on AR Foundation. Initially three Particle Systems per effect with Alpha Blend, World Collision, and Sub-Emitters—iPhone 12 ran at 45–50 FPS against a 60 FPS target. After switching to Additive + Planes Collision + merging into one Renderer with Texture Sheet—stable 60 FPS. Visual quality dropped minimally, unnoticed in playtests. Proper optimization saves project time and budget.

Integration with AR Foundation

Particles must correctly interact with the AR environment:

• Position effects on ARPlane using Pose from ARRaycastHit.
• Occlusion: particles should hide behind real objects. Implemented via ARKit/ARCore Occlusion (AROcclusionManager)—with Human/Environment Occlusion enabled, particles are automatically masked by real-world depth.
• Lighting: AREnvironmentProbeManager generates a real-time Light Probe from the environment—particles with Lighting Mode: Scene Color pick up real illumination, improving effect immersion in the AR scene.

What's included

Cost is calculated individually after discussing the effect list and target devices. Typical range: $500–$2000 per effect. We guarantee support for one month after delivery.

Contact us for a consultation on particle optimization for your hardware. We'll help achieve stable 60 FPS even on mid-range mobile devices. Request a project evaluation—we'll prepare a technical proposal.

Unity Particle System Optimization

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.