Prototype media from the existing Grid Builder project assets.
Additional existing project media; replace with a more specific placement or validation frame when available.
Section 03
Project Overview
This project is a grid-based building system developed in Unity to explore object-oriented programming, modular gameplay systems, and practical software architecture.
Inspired by builder-style games such as Clash of Clans and SimCity, the primary goal was to create a reusable foundation for building placement rather than develop an entire city simulation.
Section 04
Engineering Challenge
A flexible placement system must translate world coordinates into discrete grid cells, validate occupancy and bounds, and support buildings with different footprints and rotations.
01
Separate grid calculations from Unity presentation logic.
02
Support single-tile and multi-tile buildings.
03
Prevent placement outside valid grid boundaries.
04
Account for footprint changes when buildings rotate.
05
Provide readable visual feedback during placement.
06
Keep building definitions configurable through data.
Section 05
System Architecture
The prototype separates grid representation, placement validation, building definitions, and visual feedback into distinct responsibilities.
Architecture diagram for the Grid Builder system, showing input, placement validation, grid occupancy, previews, and pooling responsibilities.
MODULE 01
Grid Core
Pure C# logic for world-to-grid coordinate conversion, tile bounds, and cell occupancy.
MODULE 02
Placement Validation
Evaluates whether a building footprint occupies valid, available grid cells.
MODULE 03
Building Definitions
ScriptableObject-based configuration for selecting and representing building types.
MODULE 04
Placement Preview
Ghost placement feedback and pooled footprint visualization during user interaction.
Section 06
Technical Implementation
The implementation focuses on the underlying placement mechanics and a maintainable division of responsibilities.
01
World-to-Grid Conversion
Converts placement positions in world space into discrete grid coordinates.
02
Tile Occupancy
Tracks occupied cells and checks whether placement remains within grid boundaries.
03
Multi-Tile Buildings
Supports structures occupying more than one grid cell.
04
Rotation-Aware Footprints
Adjusts the occupied footprint according to building rotation.
05
Placement Feedback
Uses ghost previews and pooled footprint visuals to communicate placement state.
06
Data-Driven Selection
Uses ScriptableObjects to support a UI-driven building selection workflow.
Section 07
Technical Deep Dive
Rotation-aware footprint validation
Problem
A building footprint cannot be validated as a fixed set of cells once the building can rotate. Its dimensions and candidate cells must be evaluated against the current orientation.
Solution
The placement flow derives candidate grid cells from the building footprint and rotation, then checks bounds and occupancy before allowing placement.
Trade-off: Keeping validation separate from visual feedback makes the rules easier to reason about, but requires the preview and commit paths to share the same validation result.
candidateCells = footprint.cellsFor(rotation)
if (!grid.isWithinBounds(candidateCells)) return Invalid
if (grid.isOccupied(candidateCells)) return Invalid
return Valid
Data-driven building definitions
Problem
Hardcoding every building type into placement logic would make the system difficult to extend and tune.
Solution
Building definitions are represented as ScriptableObjects so selection and footprint data can be configured independently from the placement system.
Trade-off: The data-driven workflow adds asset setup overhead, but reduces branching in gameplay code and supports more consistent iteration.
Section 08
Validation & Known Checks
Bounds validation
Method: Attempt placement near and beyond the grid boundary with different footprint sizes.
Result: The placement rules account for the complete footprint rather than checking only the cursor cell.
Occupancy validation
Method: Attempt placement over occupied and available cells.
Result: Placement feedback distinguishes available cells from cells that cannot accept another building.
Rotation validation
Method: Rotate multi-tile footprints before checking candidate cells.
Result: The candidate footprint is recalculated for the active orientation before placement is committed.
Section 09
Results & Key Learnings
Outcomes
✓Implemented the MVP grid and placement mechanics described in the project.
✓Established a reusable foundation for expanding the builder prototype with additional gameplay systems.
Key Learnings
→Separating system responsibilities using object-oriented design.
→Applying single-responsibility principles to gameplay architecture.
→Using ScriptableObjects for data-driven configurations.
→Applying object pooling to repeated visual elements.
→Designing gameplay systems for future iteration and extension.
