Rain visualization involves creating thousands of falling particles that create the illusion of precipitation. The challenge is maintaining performance while creating a convincing effect.

Rain uses a particle system with:

• Vertical motion: Particles fall downward with gravity
• Randomized speeds: Each particle falls at slightly different rates
• Trail effects: Optional trails create streaks of rain
• Splash effects: Particles can create splashes on surfaces

Rain systems require careful optimization:

• Instanced rendering: Render many particles efficiently
• LOD system: Reduce particle count at distance
• Culling: Only render particles in view
• GPU acceleration: Use compute shaders when available

Rain visualization can include:

• Streaks: Long vertical lines representing falling rain
• Splashes: Particle effects when rain hits surfaces
• Mist: Fog-like effects from heavy rain
• Reflections: Water reflections on surfaces

Rain shaders typically use:

• Alpha blending: For transparency
• Motion blur: For streak effects
• Depth testing: To ensure proper layering
• Billboarding: To face the camera

• 3d Background - Atmospheric Effects - Main atmospheric effects page
• 3d Background - Atmospheric Effects - Fog Visualization - Fog effects
• 3d Background - Atmospheric Effects - Snow Visualization - Snow effects
• An adventure with 3js 3d Backgrounds - Overview of the 3D background system