Visibility Roadmap for Dynamic Camera Path Planning

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Solution Overview

Problem

Current camera path planning in virtual environments for computer graphics and games faces challenges in maintaining visibility of moving objects and characters, particularly in complex 3D spaces, leading to discontinuous jumps and collisions, as existing methods are often local and not well-suited for fast-moving characters or complicated visibility situations.

Innovation Solution

A graph structure representing a geometric model space partitioned into clear subvolumes is used to determine camera paths, allowing for real-time calculation of camera movements that keep a focus point in view by precomputing visibility weights and using a visibility roadmap to find collision-free paths, which can be refined for more accurate transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a local camera model is used to resolve occlusions, then the camera can handle some visibility situations, but it leads to inherent limitations such as discontinuous jumps and inability to follow fast-moving characters adequately

Engineering Contradiction:
Improvevisibility maintenanceVSAvoidcamera control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The configuration space is segmented into discrete nodes and edges forming a roadmap structure. This segmentation allows the global camera model to systematically explore visibility regions and transition between them, avoiding the discontinuous jumps of local models while maintaining comprehensive visibility coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution transitions from local 3D space reasoning to a higher-dimensional configuration space representation. By mapping camera positions and visibility states into a roadmap graph, the system achieves global optimization that prevents occlusions and discontinuities while following fast-moving characters smoothly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If a global camera model is implemented to handle large-scale transitions, then the camera can follow characters naturally without discontinuous jumps, but the computational complexity increases

Engineering Contradiction:
Improvecamera movement smoothnessVSAvoidcomputational requirements
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The visibility roadmap is pre-computed offline by partitioning the configuration space and establishing connectivity between nodes. This preliminary action separates the computationally intensive roadmap construction from real-time execution, allowing smooth global camera transitions during runtime with minimal computational overhead.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The visibility roadmap acts as an intermediary data structure that mediates between the complex 3D environment and the real-time camera control system. By querying this pre-computed roadmap, the system achieves smooth global camera transitions without directly computing visibility in real-time, thus reducing computational complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If real-time camera path computation is performed, then the system can respond to player movements immediately, but the computational load may be insufficient for complex visibility calculations

Engineering Contradiction:
Improvecamera response timeVSAvoidcomputing power
Core Design Contradiction:
SpeedVSPower

Solution Approach 1:

The visibility roadmap is constructed in advance during an offline phase, storing pre-computed visibility information in a graph structure. During real-time gameplay, the system only needs to query this pre-computed roadmap, reducing the computational load from complex visibility calculations to simple graph traversals that can be executed immediately in response to player movements.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8576235B1Visibility transition planning for dynamic camera control
Publication Date: 2013.11.05 DISNEY ENTERPRISES INC
  • US8576235B1 patent drawing
  • US8576235B1 patent drawing
  • US8576235B1 patent drawing

AI summary

A camera control system is provided that uses global planning to compute large, occlusion free camera paths through complex environments, incorporating visibility of a focus point into the search strategy, so that a path is chosen along which the focus target is in view or, in general, to compute a visibility graph. A visibility roadmap data structure permits precomputation of coarse representations of collision-free paths through an environment, together with estimates of pair-wise visibility between scene portions. At runtime, path planning can be done using the precomputed roadmap values to find a coarse path, and then refined to the camera path using occlusion maps computed on-the-fly. Iterative smoothing, together with a physically-based camera model, can be used to have the path followed by the camera smooth in both space and time. The data structure can be adapted at runtime to deal with dynamic occluders that move in an environment.