Technical Design Document

Overview

This document outlines the advanced technical solutions and optimization strategies behind our real-time terrain manipulation game prototype, Griidy, developed in Unreal Engine. The core innovation is indirect player control: instead of driving spherical characters directly, players manipulate the terrain—composed of numerous capsule-shaped modules—that dynamically move to guide character movement. This fresh approach not only defines strategic, physics-driven gameplay but also aligns with our broader mission to create an open-source, educational resource for the Unreal Engine community, as highlighted in the Griidy MegaGrants Application Strategy.

By offering fully open-source project files and a comprehensive tutorial series, Griidy aims to empower developers of all levels to explore new ways of handling physics, terrain deformation, and multiplayer networking. Ultimately, the systems described here will serve as a community foundation—an accessible blueprint for anyone interested in advanced real-time terrain manipulation techniques.

Core Systems

1. Terrain Deformation System

At the heart of Griidy lies a robust terrain deformation system. Rather than simply tilting a static arena, our design enables dynamic vertical shifts in individual terrain “capsule modules” as players apply “attractor” inputs. This approach produces unpredictable and emergent gameplay interactions that underscore Griidy’s design philosophy: players shape the world to influence character movement.

Indirect Control and Physics Synergy

Because Griidy is built around indirect control, the real-time physics interactions between terrain and player-controlled spheres become the primary driver of gameplay outcomes. This concept, noted in our MegaGrants Application Strategy, demonstrates a unique form of player agency and a creative use of Unreal Engine’s physics subsystem that can inspire and educate other developers.

2. Hierarchical Instanced Static Mesh (HISM)

Each terrain module measures roughly 25×25×200 cm. Managing these numerous, independently moving modules in real-time requires a high degree of rendering efficiency:

Batching with HISM

We utilize Hierarchical Instanced Static Mesh (HISM) technology to reduce draw calls and keep GPU performance overhead manageable. Hundreds of modules can be rendered simultaneously under a single GPU operation. This ensures the game retains stable frame rates even when players trigger extensive deformation across the entire playfield.
Community and Educational Value

As highlighted in the Griidy MegaGrants Application Strategy, we plan to release detailed tutorials showing how to set up HISM for massive dynamic environments. These resources will help fellow developers understand the benefits of batching in large-scale interactive scenes—particularly useful for level designers and technical artists seeking to optimize performance.

3. World Position Offset (WPO)

To deliver instantaneous vertical shifts without overburdening the CPU:

GPU-Driven Vertex Displacement

We use World Position Offset (WPO) shaders for moving vertices vertically on the GPU. Offloading these computations significantly reduces CPU load, allowing real-time terrain manipulation to remain fluid—especially crucial for multiplayer modes where many players might deform the terrain simultaneously.
Emergent Multiplayer Use Cases

In line with our vision of “physics-driven chaos,” Griidy’s multiplayer environment benefits from WPO because each player’s actions can instantly reshape the terrain for everyone else. This synergy demonstrates how WPO can be leveraged for networked physics—a key technical hurdle often cited by the Unreal community. Our open-source release will include example Blueprints and commentary to help developers incorporate GPU-driven transformations in their own projects.

4. Real-Time Render Target Painting

Beyond simple vertex offset, we employ an advanced render target-based painting system to capture and translate player input into both visual and physical deformations. This approach enables:

Three-Texture Workflow
1. Current State Render Target – Tracks the existing terrain deformation status.
2. Desired State Render Target – Stores intended deformation based on player inputs.
3. Render State Render Target – Smoothly transitions the terrain from current to desired states, ensuring visually appealing updates.
GPU-to-CPU Latency and Future C++ Optimization

Reading back texture data introduces slight latency, but our tests show it remains far more performant than purely CPU-based methods. In the future (and with the support outlined in the MegaGrants Application Strategy), we plan to optimize this workflow in C++ to further reduce latency. Detailed tutorials will cover the step-by-step process of setting up multi-texture render targets, bridging a knowledge gap for aspiring technical artists and rendering enthusiasts.

5. Dynamic Collider Pooling Optimization

Any real-time deformable terrain introduces collision complexities. Traditional setups require a collider per terrain module—prohibitively expensive at scale. Griidy’s dynamic collider pooling solves this:

Collider Pool Strategy

Instead of thousands of colliders, we maintain a pool of around 41 that reposition based on current gameplay needs. The system automatically detects areas of high player activity and teleports colliders into those hotspots, ensuring the level always provides reliable collision while minimizing overhead.
Teleportation & Real-Time Dynamic Positioning

When a collider is no longer needed in one area, it’s instantly teleported to a zone requiring collision. This approach delivers seamless collision accuracy without incurring CPU costs for thousands of static colliders.
Educational Case Study

As noted in the Griidy MegaGrants Application Strategy, we view this collider-pooling system as a prime example of a high-level optimization pattern with direct real-world utility. Our forthcoming tutorial content will explain the logic and blueprint setup in detail—an invaluable reference for those tackling dynamically shifting environments.

Advanced Optimizations and Extended Capabilities

GPU-Driven Terrain Updates

By pairing WPO with the HISM approach, Griidy offloads a substantial amount of terrain calculations to the GPU. This ensures the CPU remains free for other tasks such as multiplayer replication and gameplay logic.

Minimal CPU Overhead for Multiplayer Scalability

Because Griidy focuses on competitive/cooperative multiplayer, it’s critical to maintain stable performance across potentially large or complex arenas. Offloading heavy lifting to the GPU, combined with dynamic collider pooling, lets us scale up the environment—or add more players—without hitting CPU bottlenecks. This is especially relevant in our plan to release mini-game modes (e.g., soccer-style challenges, racing, platforming) that rely on real-time terrain changes.

Niagara & Future Visual Enhancements

Future versions of Griidy will integrate Niagara particle systems for more dynamic feedback. For example, we can spawn effects where the terrain shifts, highlighting abrupt changes or collisions in a visually engaging way. This advanced usage, once documented, will add to the project’s educational value, aligning with the Griidy MegaGrants Application Strategy’s emphasis on continuous expansion and open sharing of new features.

Unique Technical Contributions

Persistent, Real-Time Terrain Deformation

Our combination of WPO, render target painting, and dynamic collider pooling is highly modular, enabling complex, emergent gameplay in real-time multiplayer scenarios—an area often avoided due to perceived performance difficulties.
Advanced Shader Communication

The use of multiple render targets to continuously track and blend deformation states yields an immediacy that greatly enhances player immersion. This entire process will be carefully documented and open-sourced to illustrate how to orchestrate GPU-driven updates in tandem with CPU logic.
Optimized Collider Management

Our collider pooling technique significantly reduces CPU burden without compromising gameplay accuracy. This design can be extended or adapted for other real-time deformable or modular systems—particularly beneficial in large worlds or procedural generation contexts.
Open-Source & Educational Approach

In direct alignment with the Griidy MegaGrants Application Strategy, all of these technical contributions will be shared publicly. We plan to offer both in-engine project files and video tutorials explaining the logic, setup, pitfalls, and future considerations. By doing so, Griidy not only introduces advanced techniques but also demystifies them for a wide developer audience.

Future Development Directions

Enhanced Interpolation & Detailed Deformations

Improving on our three-render-target workflow to support finer gradients or advanced interpolation. This could lead to more nuanced, visually rich terrain manipulation, particularly useful in aesthetic or cinematic contexts.
Expanded Collider Pooling for Larger Worlds

As the game scales, we may raise the number of pooled colliders or refine the logic to handle even larger player counts. This approach has applications in massively multiplayer or large open-world games where dynamic terrain or structures must remain feasible.
Integration with Additional Unreal Engine Features
- Niagara Particle Systems for responsive VFX tied to terrain deformation.
- Lumen or other real-time global illumination solutions to maintain a consistent lighting experience despite frequent vertical shifts in the level.
- Nanite (if feasible) or Virtual Textures for improved resource management on next-gen hardware.
C++ Modules for Texture Processing

Reducing readback latency from GPU to CPU is a key goal. Collaborations with specialized developers or further in-house C++ experimentation will help push real-time terrain manipulation to new performance heights—paving the way for future expansions or spin-off projects within the open-source Griidy ecosystem.

Open-Source and Community Impact

Alongside these technical innovations, Griidy is structured as a community-driven project:

Free, Open-Source Release

Every Blueprint, material setup, and optimization strategy will be made publicly available so developers can learn directly from the complete production build.
Comprehensive Tutorial Series

True to the vision outlined in the Griidy MegaGrants Application Strategy, we will produce a series of step-by-step tutorials covering everything from initial terrain module setup to advanced GPU-CPU communication. These tutorials are intended for a range of skill levels, ensuring that both newcomers and experienced developers gain insights into advanced Unreal Engine workflows.
Potential Official Sample Project

We propose collaborating with Epic Games to feature Griidy as an official sample project, merging the open-source code with our end-to-end tutorial series. This approach would create a living reference for the Unreal Engine community, showcasing how to design, optimize, and network a truly dynamic physics game.
Long-Term Community Value

By transparently documenting each system, Griidy aims to lower the barrier to building physics-based, indirectly controlled, or massively deformed environments in Unreal Engine. Our pipeline—from conceptualizing attractor-based control to final deployment—stands to inspire new mechanics in party games, puzzle platforms, or experimental simulations. Moreover, the MegaGrant support would allow us to devote the time needed to maintain and update these learning materials, ensuring lasting educational value.

Conclusion

The technical framework of Griidy represents more than a single game prototype—it is a blueprint for innovative real-time terrain manipulation, grounded in robust optimization strategies. By combining HISM batching, GPU-driven vertex displacement, multi-texture render targets, and dynamic collider pooling, Griidy achieves real-time deformation that remains responsive even in multiplayer scenarios.

Importantly, we aspire to share every facet of this system as a free, open-source resource, supplemented by an extensive video tutorial series. As described in the Griidy MegaGrants Application Strategy, this community-first focus aligns perfectly with Epic’s mission to empower creators, advance the real-time 3D space, and cultivate knowledge among Unreal Engine users. By pushing the boundaries of terrain-based gameplay and enabling others to replicate or improve upon our work, Griidy contributes technical expertise that can fuel the development of future games, tools, and educational initiatives within the Unreal ecosystem.

Through this synergy of technical innovation and community-driven values, Griidy sets the stage for a new era of physics-based fun—and invites everyone to learn, iterate, and create alongside us.