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:
- Profile current effects to identify bottlenecks using Unity Profiler.
- Choose blending strategy: replace Alpha Blend with Additive where possible.
- Optimize collision: switch from World to Planes Collision.
- Merge materials and enable GPU Instancing.
- 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
| Stage | Deliverable |
|---|---|
| Requirements analysis | List of effects, target devices, visual fidelity requirements |
| Technical design | Choice of Particle System vs VFX Graph, overdraw strategy, collision approach |
| Effect development | Creation with optimization from scratch, not retrofitting |
| Profiling | Unity Profiler + Xcode Instruments / Android GPU Inspector on target devices |
| AR Foundation integration | Anchoring to AR surfaces, occlusion, lighting |
| Documentation and training | Source files, setup guide, team consultation |
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.
| Number of effects | Estimated timeline |
|---|---|
| 3–5 basic effects | 1–2 weeks |
| 10–15 effects with AR integration | 3–5 weeks |
| Complex systems with GPU Instancing and VFX Graph | 1–2 months |
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.