Orientation-Based Combat

1. Overview

Pattern Level: High-level 
Primary Phase: Presenting
One-line Summary: A challenge mechanic that uses head orientation tracking to let players evade spatially positioned threats, turning the same sensing infrastructure used for navigation into an active skill-based game mechanic.
Source: Voices of the Boyne (Battle of Boyne, Hill of Tara, National Botanic Garden)

Name

• Orientation-Based Combat

Intent

To introduce a challenge mechanic that uses the same sensors and spatial audio infrastructure already present in the experience, without requiring any screen interaction or additional hardware. The player’s physical body becomes the controller, and spatial awareness becomes a skill that matters for more than just finding characters.

2. Target

Problem

In most location-based games, interactive challenge mechanics rely on touchscreen inputs that pull attention to the screen and away from the physical environment. In an audio-first experience where screen use is actively discouraged, these mechanics are not available. The deeper challenge is that in a location-based game driven by position and orientation tracking, the measurable actions a player can take are limited. The system knows where you are and which way you are facing. Finding ways to make orientation feel like active gameplay rather than passive navigation is therefore a meaningful design problem.

Context

• Players have been navigating the site and completing character encounters.
• Specific artefact combinations collected from encounters trigger a combat sequence.
• IMU head tracking is active and providing reliable heading data.
• The player is in an open outdoor space with enough room to rotate their head.
• Combat replaces Wander and Interact modes for its duration.

Use When

• A player has collected a specific combination of artefacts that the system recognises as a combat trigger.
• The experience needs a risk and reward mechanic to balance the reward of artefact collection.
• A skill-based physical challenge is needed that works without visual feedback or screen interaction.
• The designer wants to use the head-tracking infrastructure for something other than navigation.

Forces

• Spatial precision vs. physical effort: evasion does not require exact facing. A threshold head turn in the correct direction counts as a successful dodge. Too small a threshold and any movement counts; too large and the mechanic becomes demanding.
• Combat intensity vs. navigation flow: combat suspends all other gameplay, creating a tonal shift and raising stakes, but also interrupting the exploration rhythm of the dual-mode system.
• Recovery effort vs. accessibility: players who take damage must navigate to a healing item, which reuses an existing skill elegantly but adds length and may frustrate players who are struggling.

Consequences

Weaknesses:

• Players with limited neck mobility or who are unable to rotate their head may find the evasion mechanic difficult.
• If the IMU sensor disconnects, the system falls back to phone sensors requiring the phone to be held upright. A phone left in a pocket will produce incorrect heading data and the evasion mechanic will not work as expected.
• Latency between a physical head turn and the system registering it can create a timing gap where the player feels they dodged correctly but the system disagrees.
• The combat encounter completely suspends exploration.

Strengths:

• Combat uses the same sensors and spatial audio infrastructure as navigation. No additional hardware is required.
• Head rotation as evasion creates a genuine sense of physical presence. Players are dodging, not pressing a button.
• The artefact combination trigger creates risk and reward around exploration.
• Recovery through navigation keeps players in the same interaction mode used throughout the experience.

3. Application

Solution

1. Approach phase — a mercenary announces the encounter with introductory dialogue. Footstep sounds begin, spatially positioned to the left or right of the player’s current heading. The footsteps move through space as the mercenary closes the distance.
2. Attack phase — an attack sound plays at close range. The player has from the start of the approach to the moment the attack resolves to turn toward the attacker.
3. Defense check — the system records the player’s heading at the start of the approach. At resolution it checks whether the player has turned 10 degrees or more toward the attacker. The first attack is always a forced hit regardless of the player’s response, ensuring they experience the damage and heartbeat feedback before the skill is needed.
4. Outcome — a successful evasion plays a block sound. A failed evasion plays a hit sound and reduces health. A heartbeat sound communicates health state, becoming more intense at lower values.
5. Recovery — if the player took damage, a healing item spawns nearby and emits a continuous spatialised audio signal. The player walks toward the sound and collects it on getting close enough.
6. Conclusion — after the introductory dialogue, the mercenary attacks in a set number of waves. When all waves are complete, a closing dialogue plays in which the mercenaries concede and leave, regardless of how much damage the player took. The player cannot lose. If the player took damage, they navigate to the healing item before Wander mode resumes. If not, Wander resumes immediately.

Rationale

• Using footstep spatialisation for the approach means the sound is itself the cue. The player must listen to understand where the threat is coming from.
• A threshold turn rather than precise facing reflects the physical reality of outdoor movement. A 10-degree turn is deliberate without being demanding.
• The forced first hit is a deliberate tutorial move. Players cannot understand the value of evasion until they have experienced the cost of being hit.
• Recovery through navigation reuses an existing skill in a new context. A player who learned to navigate toward audio cues does not need to learn anything new to find the healing item.
• The player can never lose. The mercenaries always concede after a fixed number of waves. This is a deliberate design decision for a public heritage site where stranding a visitor in a failing state is not acceptable.

Design Parameters

Example

A player collects a Grenade from the Grenadier and a Royal Seal Ring from King James II. The system recognises this combination. A mercenary’s voice announces his intention to take the artefacts back. Footsteps approach from the right. The player turns right. Blocked. Second wave from the left. Blocked again. Third wave from the right. The player is a fraction too slow. A hit sound plays and the heartbeat quickens. The mercenary’s closing dialogue plays. A gentle music begins from the northwest, about 11 metres away. The player walks toward it and collects the healing item. The heartbeat settles. Wander mode resumes.

Implementation Notes

• Record the player’s exact heading at the start of each approach phase. The defense check compares current heading to this recorded value, not to an absolute direction.
• Attack bearing should be constrained to left or right of the recorded heading. Front and rear attacks are harder to localise accurately in outdoor spatial audio.
• The footstep audio should move spatially during the approach phase, simulating the mercenary closing the distance.
• Healing item GPS position is calculated at spawn time using a bearing and distance offset from the player’s current location. It is not a fixed map position.

Evidence / Source

• Deployed at Battle of Boyne heritage site.
• User testing confirmed players could identify attack direction from footstep spatialisation alone, without additional warning cues.

Composition Recipes

Recipe	Scenario	Guiding	Indicating	Presenting + Notes
R1	Artefact-triggered combat	Head-Directed Target Locking used to navigate to artefact-bearing characters	Audio-First Dual-Mode manages encounters that yield artefacts	Orientation-Based Combat triggers when the artefact combination threshold is met
R2	Combat and recovery cycle	Recovery navigation toward healing item reuses directional audio mechanic	Audio-First Dual-Mode suspended during combat	Orientation-Based Combat resolves, healing item spawns, player navigates to it, Wander resumes
R3	Tutorial combat introduction	Single tutorial character navigation	Audio-First Dual-Mode tutorial encounter	Orientation-Based Combat with forced first hit teaches the mechanic before skill is tested