Game Design Document

Overview

Griidy is a cutting-edge, physics-based multiplayer party game that revolutionizes character control by introducing indirect manipulation mechanics. Unlike traditional games, players do not directly control characters; instead, they strategically modify a dynamic, modular environment constructed from vertically adjustable capsule-shaped terrain units. This innovative gameplay design fosters creativity, strategic thinking, and emergent interactions as players continuously adapt the terrain to guide spherical avatars toward diverse objectives.

Powered by Unreal Engine, Griidy employs sophisticated real-time physics simulations to manage terrain deformation, avatar momentum, collision detection, and interactive gameplay scenarios. Key components of the game's innovative design include:

Indirect Control Mechanics

Players control avatar movement indirectly by manipulating the terrain—raising, lowering, or tilting modules to guide their characters. This novel approach creates an accessible yet deeply strategic gameplay experience seldom explored in multiplayer contexts.

Physics-Based Gameplay

Harnessing Unreal Engine's robust physics engine, each gameplay session unfolds uniquely through spontaneous, unpredictable outcomes. Real-time physics interactions significantly enhance replayability, delivering varied and engaging experiences with each match.

Dynamic Terrain System

The terrain system consists of modular capsule-shaped units, efficiently managed through Unreal Engine's Hierarchical Instanced Static Mesh (HISM) technology. Terrain deformation is visually dynamic and responsive, utilizing World Position Offset (WPO) shaders and a sophisticated render-target-based painting system, providing instantaneous and fluid visual feedback.

Collider Optimization

Griidy implements an advanced dynamic collider pooling system that markedly reduces computational load. This optimization ensures fluid, responsive gameplay performance even in highly active multiplayer sessions.

Designed for both local and online multiplayer gameplay, Griidy supports competitive, cooperative, and hybrid game modes, appealing broadly through its accessible mechanics and gameplay depth. Moreover, Griidy emphasizes community engagement and education, committing to an entirely transparent development process. Comprehensive tutorials and open-source resources will be provided, positioning Griidy as both an innovative gaming experience and a valuable educational resource within the Unreal Engine community.

Development Team & Cross-Disciplinary Influence

Griidy is developed by a team that brings together diverse backgrounds in architecture, extended reality (XR), and product-service systems design. This cross-disciplinary approach fuels every aspect of Griidy’s creation—from spatially inspired terrain layouts to a user-centric interface and tutorial structure. Thanks to prior university-level teaching experience, the team can break down advanced concepts (e.g., GPU-driven terrain deformation, dynamic collider pooling) into accessible tutorials, ensuring developers of all levels can grasp the project’s technical depth.

Mission Statement

Griidy’s mission is to deliver a technically innovative multiplayer experience through its unique indirect control scheme—empowering players to shape terrain in real time to influence character movement. This novel approach leverages a suite of advanced Unreal Engine systems, including World Position Offset (WPO) shaders, Hierarchical Instanced Static Meshes (HISM), and a multi-layered render target painting workflow to simulate dynamic terrain deformation at scale.

More than just a game, Griidy is designed as a fully open-source educational platform. The project will be released with complete Unreal Engine source files and an extensive tutorial series that covers every stage of development, from modular terrain logic and real-time physics interactions to performance optimization and multiplayer replication. By integrating advanced concepts into a playable, polished experience, Griidy provides the Unreal Engine community with a rare, high-quality sample project that doubles as a comprehensive learning resource. It is our goal to democratize access to complex game development techniques, contributing meaningfully to the education and growth of developers worldwide.

Community, Education, and Epic Alignment

Griidy aligns strongly with Epic Games’ emphasis on innovation, open-source collaboration, and community empowerment. By sharing complete project files, Blueprint logic, and minimal C++ modules, the team aims to lower the barrier to entry for newcomers. These efforts not only benefit aspiring developers but also resonate with Epic’s mission to support experimental, high-quality projects that add value to the real-time 3D community. Through dedicated tutorial series, code demonstrations, and proactive community engagement, Griidy aspires to be an exemplary resource that embodies Epic’s philosophy of creators helping creators.

Genre

Physics-Based Multiplayer Party Game

Griidy blends the accessibility of party games with the emergent complexity of real-time physics, delivering a gameplay experience that is both chaotic and deeply strategic. Unlike traditional character control schemes, Griidy’s indirect control model tasks players with manipulating a modular terrain system to influence spherical avatars, introducing a fresh layer of spatial reasoning and tactical interaction.

Its genre-defining features include:

Emergent Physics Gameplay: Every session produces unpredictable, system-driven outcomes rooted in Unreal Engine’s physics simulation.
Indirect Terrain-Based Control: Players manipulate vertically movable capsule modules, requiring foresight and coordination.
Dynamic Multiplayer Modes: Griidy supports competitive, cooperative, and hybrid game types, optimized for both local and online play.
Strategic Terrain Manipulation: Elevation, momentum, and environmental design become core mechanics, creating gameplay scenarios reminiscent of puzzle-solving, platforming, and tactical sports.

This hybrid of physics sandbox, party game, and spatial strategy positions Griidy as a genre-pushing title—ideal for players seeking creativity, challenge, and multiplayer mayhem within a uniquely interactive environment.

Platform

Primary Platform: PC ( Windows - Mac )

Griidy is being developed primarily for PC, leveraging the platform’s flexibility and high-performance environment to support both development and educational objectives. By targeting PC first, the project ensures maximum compatibility with Unreal Engine’s editor, allowing developers to fully explore and interact with the open-source project files.

Although the initial release is PC-exclusive to maximize accessibility for developers and learners, Griidy is architected for cross-platform scalability. Future adaptations for consoles or other hardware platforms are planned, aligning with the project’s long-term goal of reaching a broader player base while maintaining technical integrity.

Target Audience

Griidy is designed to engage a broad and diverse audience across both gameplay and development communities. As a multiplayer party game with intuitive mechanics and emergent physics, it appeals to casual players, friend groups, and competitive gamers alike—regardless of age or experience. Its chaotic-yet-strategic gameplay encourages laughter, improvisation, and replayability, making it well-suited for social play environments both online and locally.

Concurrently, Griidy’s open-source framework and accompanying tutorial series are tailored for Unreal Engine developers of all levels. The project is built almost entirely using Blueprint visual scripting, making it highly approachable for beginners, students, and hobbyists. For more experienced developers, the educational content explores advanced concepts such as GPU-based terrain manipulation using WPO and render target sampling, with limited C++ used only where necessary (e.g., reading render target textures).

Whether approached as a party game or a technical case study, Griidy serves as both an entertaining experience and a robust learning platform—demonstrating how high-quality systems can be built primarily in Blueprints, and shared for the benefit of the wider Unreal Engine community.

Gameplay

Gameplay Overview

Griidy’s core gameplay revolves around an innovative indirect control mechanic where players manipulate a dynamic, modular terrain system to influence spherical avatars. Players strategically adjust terrain modules along the Z-axis—moving them vertically upward or downward—to guide their avatars indirectly. The game prioritizes strategic foresight, rapid adaptation, and creative problem-solving, with each interaction leading to unique, emergent outcomes.

Terrain Modules

The primary interactive elements in Griidy are the terrain modules—capsule-shaped units arranged in a grid-based configuration. Players manipulate these modules vertically, adjusting their positions along the Z-axis to shape the game environment. The dynamic repositioning of these modules directly influences avatar trajectories and behaviors.

Key features of terrain modules:

Vertical Movement: Modules can be raised or lowered individually or collectively, altering the terrain's elevation.
Real-time Responsiveness: Instant feedback through GPU-driven techniques such as World Position Offset (WPO) ensures fluid visual representation.
Strategic Utility: Modules can be manipulated to create paths, barriers, ramps, or launch pads, offering diverse tactical possibilities.

Indirect Control Mechanism

Griidy's defining feature is its indirect control mechanism, which differs from traditional character control schemes. Players influence their avatars by repositioning terrain modules, using environmental manipulation to indirectly steer the avatars toward objectives. This system requires continuous real-time assessment and strategic adjustment of terrain to maintain desired avatar trajectories.

Highlights of the indirect control:

Attractors: Specialized tools enabling players to target and adjust terrain modules dynamically.
Emergent Gameplay: Avatar movement emerges organically from physical interactions with manipulated terrain modules, resulting in unpredictable yet manageable scenarios.
Skillful Adaptation: Players develop skills in predicting physics-based interactions and quickly adapting to changing game states.

Avatars and Physics Simulation

Avatars in Griidy are physics-simulated spherical objects that move based on momentum, gravity, collisions, and interactions with terrain modules. Players do not directly control avatars; instead, their movement results from the environment's strategic manipulation.

Important characteristics of avatars include:

Physics-based Movement: Realistic momentum, bouncing, rolling, and collision physics powered by Unreal Engine.
Responsive Dynamics: Immediate physical responses to terrain adjustments ensure gameplay fluidity and realism.
Interactive Complexity: Collisions between avatars, modules, and environmental objects result in dynamic, emergent outcomes.

Multiplayer Dynamics

Griidy emphasizes multiplayer interaction, supporting various competitive and cooperative gameplay modes. Players interact either collaboratively or competitively, influencing one another through shared terrain manipulation and avatar interactions.

Multiplayer features include:

Competitive Modes: Players strategically compete to achieve objectives, such as scoring goals or controlling key positions.
Cooperative Modes: Players collaborate, manipulating terrain collectively to navigate complex obstacle courses or achieve shared objectives.
Hybrid Interaction: Unique scenarios that blend competition and cooperation, fostering dynamic and social gameplay experiences.

Game Modes and Objectives

Griidy offers a variety of game modes catering to different play styles and preferences, each with distinct objectives and win-loss conditions. These modes leverage the core mechanics to provide diverse gameplay experiences.

Examples of game modes:

Sports-inspired Modes: Games inspired by football, where terrain manipulation is crucial for goal-scoring and defense.
Obstacle Arenas: Cooperative or competitive challenges involving complex obstacle navigation via terrain manipulation.
Survival and Score-based Objectives: Gameplay scenarios where players must strategically control terrain to achieve specific survival or scoring goals.

By focusing on indirect control, dynamic terrain manipulation, and robust physics simulation, Griidy offers an innovative multiplayer experience that encourages strategic thinking, creative problem-solving, and engaging social interactions.

Game Visuals, Aesthetics, and UI

Visual and Artistic Style

Griidy embraces a clean, modern visual style characterized by vibrant colors, intuitive design, and visually appealing animations. The modular terrain and spherical avatars are aesthetically cohesive, emphasizing clarity and readability during fast-paced gameplay. Consistent use of color and shape reinforces the game's accessibility while highlighting dynamic interactions.

User Interface Design

The user interface (UI) in Griidy is designed with clarity and accessibility as core principles, ensuring players can easily interact with complex systems. Essential gameplay information, such as objectives, player statuses, and scores, is clearly displayed with minimal visual obstruction. Interactive elements, including attractor tools and terrain manipulation indicators, provide immediate visual feedback, reinforcing intuitive control and engagement.

Animations and Effects

Fluid animations and dynamic visual effects enhance gameplay immersion and clearly communicate interactions and game states. Terrain adjustments, avatar movements, and collision impacts are visually distinct, providing critical feedback to players in real-time. Strategic use of particle effects, subtle visual cues, and responsive animations ensures an engaging and informative player experience.

Conclusion

Griidy represents a bold step forward in multiplayer gaming, combining innovative indirect control mechanics with real-time physics-based interactions. By strategically manipulating dynamic terrain modules, players experience a fresh and engaging approach to gameplay that challenges their strategic thinking and adaptability. Designed with both entertainment and education in mind, Griidy not only aims to provide a memorable multiplayer experience but also serves as an accessible, high-quality educational resource for developers exploring advanced Unreal Engine techniques. Moving forward, our goal remains focused on community engagement, continuous improvement, and expanding the game's creative possibilities to ensure lasting appeal and value to players and creators alike.