3D Terrain Data Visibility Map for Mobile Rendering
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Solution Overview
Problem
Existing methods for rendering three-dimensional terrain data on mobile devices face limitations due to high data transfer speeds and memory constraints, particularly when using slow network connections, leading to inefficient data loading and potential 'holes' in the representation.
Innovation Solution
A method that prioritizes loading geometry data before texture data, using visibility conditions and a predefined quality factor based on distance from the observation point to selectively request and download only the necessary texture data blocks, reducing data traffic and memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all data sections from the lowest to the highest detail level are loaded while traversing down a tree structure, then the rendering quality is maintained without holes in the representation, but the data transfer time and memory requirements increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing visibility information in a visibility map before rendering. This visibility map pre-identifies which data sections are actually visible from the observation point, allowing the system to skip loading invisible sections entirely. The visibility map is created by projecting the 3D terrain geometry onto a 2D grid from the observer's viewpoint, marking only the visible portions that need to be rendered.
Solution Approach 2:
The patent extracts only the necessary visible portions of terrain data by using the pre-computed visibility map to selectively load data sections. Instead of loading all data sections from the tree structure, the system extracts and loads only those sections marked as visible in the visibility map, significantly reducing data transfer while maintaining rendering quality for visible areas.
2Quantity of substance
If data is subdivided into smaller data blocks with multiple representation versions at different detail levels, then the memory storage and data transfer requirements are reduced, but the complexity of selecting and managing the appropriate data blocks increases
Solution Approach 1:
The patent segments the terrain data into a hierarchical tree structure where the root node represents the complete terrain and child nodes represent progressively smaller data sections at higher detail levels. Each node contains metadata about its spatial extent and detail level. This segmentation allows the system to efficiently select and load only the specific segments needed for rendering, organized in a manageable hierarchical format.
Solution Approach 2:
The patent applies local quality by assigning different detail levels to different spatial sections of the terrain based on their visibility and importance. The visibility map determines which local regions need high-detail representation and which can use lower-detail representations. This allows the system to maintain high quality where needed while using compressed or lower-resolution data elsewhere, optimizing both quality and data volume.
3Reliability
If the network connection is slow, then the data transfer time increases significantly, but loading all necessary data sections is required to maintain rendering quality
Solution Approach 1:
The patent performs preliminary action by pre-computing the visibility map that identifies exactly which data sections are visible from the observation point. This pre-computation allows the system to prepare an optimized data loading plan before actual data transfer begins, ensuring that only visible sections are requested even when network speed is slow, thus maintaining rendering quality while minimizing transfer time.
Solution Approach 2:
The patent extracts only the visible data sections identified by the visibility map, excluding all invisible portions from the data transfer process. This extraction approach ensures that even with slow network connections, the system transfers minimal data while maintaining complete rendering quality for all visible terrain features.
4Reliability
If the memory of the mobile device is used to store all needed data for rendering, then the rendering quality is maintained, but the memory capacity is insufficient for large three-dimensional data sets
Solution Approach 1:
The patent performs preliminary action by pre-computing and storing the visibility map that identifies which terrain sections are visible from the observation point. This pre-computation allows the system to determine exactly which data sections need to be loaded into memory, excluding all invisible sections. The visibility map itself is stored in memory rather than the complete terrain data set, dramatically reducing memory requirements while maintaining rendering quality for visible areas.
Solution Approach 2:
The patent extracts only the visible data sections identified by the visibility map and loads them into memory, excluding all invisible portions. This extraction approach ensures that memory capacity is used efficiently, storing only the necessary data for current rendering while maintaining complete quality for all visible terrain features.
Data Source
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AI summary
Method (100) for providing a set of data files from a server computer (40) to a mobile client device (30), the set of data files comprising texture data (21-23) being associated with a portion of a three-dimensional surface (25) in an image scene (20), wherein the image scene (20) is defined by an observation point and a direction and/or angle of view, the set of data files is a subset of data files being stored on the server computer (40), and each data file comprises texture data (21-23) in one of a plurality of different detail levels (331-335), characterized in that the method (100) comprises providing geometry data in a memory of the mobile client device (30), the geometry data being associated with the three-dimensional surface in the image scene (20), selecting data files with texture data (21-23) for being provided by the server computer (40), wherein selecting data files is performed by a calculation unit of the client device (30) based on the geometry data and on visibility conditions of the three-dimensional surface (25) in the image scene (20), and requesting the provision of the selected data files from the server computer (40) to the client device (30).