100 GPU-animated fish in one ready-to-use Blueprint. HISM rendering, 100 unique baked movement paths and procedural GPU vertex animation — without skeletal swimming animation.

SchoolFish 100 is a ready-to-use fish school Blueprint for Unreal Engine 5, designed for underwater environments, ocean scenes, aquariums and large-scale aquatic worlds.

100 animated fish are included in each school. Every fish follows its own unique baked movement trajectory, while swimming and tail deformation are generated in real time using GPU vertex animation.

The fish are rendered using Hierarchical Instanced Static Mesh (HISM), reducing the rendering overhead compared with using many individual mesh components.

KEY FEATURES

• 100 animated fish per school

• 100 unique baked movement trajectories

• HISM-based rendering

• GPU vertex animation for swimming and tail movement

• No Skeletal Mesh required for swimming deformation

• No bone-based swimming animation

• 31-second seamless animation loop

• Individual swimming phase variation

• Ready-to-use Blueprint actor

• Easy drag-and-drop setup

• Designed for large underwater environments

HOW IT WORKS

Each fish follows its own pre-baked movement trajectory. The trajectory controls the position and rotation of the corresponding fish.

Swimming and tail movement are generated procedurally on the GPU using vertex displacement. This allows the fish to swim without traditional skeletal animation for the swimming deformation.

HISM is used to render the fish as instances, keeping the rendering cost of the fish geometry very low even when multiple schools are placed in the scene.

PERFORMANCE TEST

The asset was tested in Unreal Engine 5 using 1, 2 and 3 SchoolFish 100 actors, representing 100, 200 and 300 fish respectively.

100 FISH

• FPS: ~82.5

• Frame Time: 12.11 ms

• GPU Time: 11.86 ms

• Draw Calls: 181

• Primitives: 45.8K

• Basepass: 0.08 ms average

200 FISH

• FPS: ~79.37

• Frame Time: 12.60 ms

• GPU Time: 12.03 ms

• Draw Calls: 181

• Primitives: 45.8K

• Basepass: 0.05 ms average

300 FISH

• FPS: ~71.04

• Frame Time: 14.08 ms

• GPU Time: 11.86 ms

• Draw Calls: 184

• Primitives: 45.8K

• Basepass: 0.07 ms average

In this particular test scene, increasing the number of fish from 100 to 300 did not produce a significant increase in GPU Time.

GPU Time:

100 fish → 11.86 ms

200 fish → 12.03 ms

300 fish → 11.86 ms

The measured Basepass cost of the fish geometry remained below 0.1 ms in all three tests:

100 fish → 0.08 ms

200 fish → 0.05 ms

300 fish → 0.07 ms

These results demonstrate the low rendering cost of the HISM and GPU vertex animation approach in this test environment.

PERFORMANCE NOTE

These measurements were recorded in a specific Unreal Engine test scene and should be used as a reference rather than a guaranteed performance target.

Benchmark Test Hardware: Ryzen 7 9700X | RTX 2070 | 32 GB

Actual performance will vary depending on hardware, screen resolution, project settings, lighting, Lumen, shadows, post-processing and the complexity of the surrounding environment.

USE CASES

• Underwater environments

• Ocean and marine environments

• Aquarium scenes

• Exploration games

• Open-world environments

• Cinematic scenes

• Educational and simulation projects

• VR underwater experiences

TECHNICAL DETAILS

Number of Blueprints: 1

Number of Static Meshes: 4 (1 fish mesh, 3 environment meshes)

Number of Skeletal Meshes: 99

Number of Skeletons: 99

Number of Animation Sequences: 99

Number of Materials & Material Instances: 8 (6 Master Materials, 1 Material Instance, 1 Material Function)

Number of Textures: 20

Texture Resolutions: 4096x4096

Supported Development Platforms: Windows

Supported Target Build Platforms: Windows

Tested Engine Version: Unreal Engine 5.4.4