NPC Imitation Region Expansion for Natural Action Timing

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Solution Overview

Problem

In games where multiple non-player characters (NPCs) mimic the actions of a player character, synchronizing their actions to avoid an unnatural appearance when they all start simultaneously.

Innovation Solution

Implementing a system where NPCs within a predetermined imitation region around the player character start their actions at different times, adjusting for elapsed time, direction, and random waiting periods, synchronized with background music timing, to create a more natural and synchronized motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all NPCs are caused to perform the same action at the same time, then the action propagation is efficient and synchronized, but the action appears unnatural and causes user discomfort

Engineering Contradiction:

Improveaction synchronizationVSAvoidunnatural appearance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the imitation region expand over time rather than remaining static. The region starts small and gradually grows to include more NPCs, causing actions to propagate naturally from nearby characters to farther ones. This temporal dynamic resolves the contradiction by maintaining synchronization within each time step while creating natural variation across the population.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses periodic action through discrete time-step updates of the imitation region. At each time step, the region expands by a fixed amount, and NPCs within the current region boundary perform actions simultaneously. This periodic expansion creates a wave-like propagation pattern that appears natural while maintaining clear synchronization boundaries.

Inventive Principle:

Principle #19Periodic action

2Quantity of substance

If the imitation region expands quickly to include many NPCs, then more characters can participate in the action, but the timing becomes less natural and more synchronized

Engineering Contradiction:

Improvenumber of NPCs performing actionVSAvoidaction timing variation

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The patent segments the NPC population into different groups based on their distance from the player character and the current imitation region boundary. NPCs are processed in discrete batches as the region expands at each time step, rather than all at once. This segmentation allows gradual inclusion of more NPCs while maintaining natural timing variations between groups.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by pre-defining the expansion rate and boundary of the imitation region before NPCs perform their actions. The region expands to a predetermined size at each time step, and only then do NPCs within that region perform their actions. This preliminary setup ensures controlled, natural timing while allowing progressive inclusion of more characters.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12544667B2Systems and methods controlling NPC actions based on an expanding imitation region

Publication Date: 2026.02.10 NINTENDO CO LTD

AI summary

A player character is caused to start a continuous action on the basis of an operation input. Every time a predetermined time elapses from the action start, a non-player character included in a predetermined range including a position of the player character and having a size corresponding to an elapsed time from the action start is determined. Then, the non-player character determined to be included in the predetermined range is caused to start the continuous action.