UE engine and webGIS engine scene linkage method
By using an event bus system and offset conversion algorithm, the problems of coordinate system differences and delays in the linkage between UE scenes and webGIS scenes were solved, achieving high-precision coordinate transformation and low-latency real-time interaction, thus improving system performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-19
- Publication Date
- 2026-04-28
AI Technical Summary
In existing technologies, when UE scenes and webGIS scenes are linked, there are problems of accuracy loss and interaction delay caused by coordinate system differences. Traditional conversion methods have large errors and cannot meet the requirements of real-time interaction.
An event bus system and an offset-based coordinate transformation algorithm are adopted. The event bus system enables low-latency data synchronization, and the Deloni triangulation and LOD control strategy are used to improve the coordinate transformation accuracy. The UE coordinate system is constructed to achieve fast rendering.
It significantly improved the coordinate transformation accuracy between the two scenarios, reduced latency, achieved real-time interactive response of less than 50ms, and improved performance by 10 times.
Smart Images
Figure CN121937650A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to electronic digital data processing, and more specifically, to a method for scene linkage between a UE engine and a webGIS engine. Background Technology
[0002] UE scenes typically refer to virtual reality or augmented reality scenes created using Unreal Engine; webGIS scenes refer to web-based geographic information systems that allow users to access and analyze geographic information within a browser. Under the current technological framework, the integration of UE scenes and webGIS scenes mainly faces the following problems:
[0003] (1) Significant differences in coordinate systems: webGIS uses the WGS84 ellipsoidal coordinate system, while UE uses the local Cartesian coordinate system. Traditional conversion methods (such as Mercator projection) suffer from accuracy loss (error > 5 meters).
[0004] (2) Significant interaction latency: When data synchronization is achieved through HTTP requests, the latency often exceeds 500ms, which cannot meet the requirements for real-time interaction. While WebSocket communication can reduce latency, it does not solve the problems of coordinate system transformation and data compression. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a scene linkage method between UE engine and webGIS engine to address the shortcomings of the existing technology, which greatly improves the accuracy of coordinate transformation between the two scenes and achieves the goal of low latency.
[0006] The present invention discloses a scene linkage method between a UE engine and a webGIS engine. When operating on a map in webGIS, the camera status in webGIS is transmitted to the UE scene through an event bus system. The UE scene extracts the camera status coordinates from the camera status and calls a coordinate transformation algorithm based on offset transformation to convert the camera status coordinates into UE coordinates in the UE scene. Then, a UE coordinate system is constructed. The Lod control strategy is called to perform fast rendering in the UE scene.
[0007] Preferably, the coordinate transformation algorithm based on offset transformation is specifically as follows:
[0008] The first step is to extract coordinate points with the same name from the coordinates of the UE scene and the camera status coordinates as control points;
[0009] The second step is to create a dot matrix based on the control points in the UE scene, and at the same time calculate the coordinate offset of the UE scene coordinates and camera state coordinates corresponding to the control points, and construct a Deloni triangulation based on the dot matrix and coordinate offset.
[0010] The third step is to use the camera state coordinates corresponding to the control point as the target point for spatial querying to obtain the triangle in the constructed Dillonian triangulation where the target point is located.
[0011] Step 4: Calculate the target offset based on the coordinates of the target point and the coordinates of the control points of the triangle corresponding to the target point;
[0012] Step 5: Calculate the position of the target point after the offset based on the target offset and use it as the UE coordinates.
[0013] Preferably, the formula for calculating the target offset is:
[0014]
[0015] Wherein, the coordinates of the target point are (x, y); the target offset is (Dx, Dy); and the coordinates of the three control points of the triangle corresponding to the target point are (x1-Dx1, y1-Dy1), (x2-Dx2, y2-Dy2), and (x3-Dx3, y3-Dy3); x 21 =x2-x1,x 31 =x3-x1,y 21 =y2-y1,y 31 =y3-y1,Dx 21 =Dx2-Dx1,Dx 31 =Dx3-Dx1,Dy 21 =Dy2-Dy1,Dy 31 =Dy3-Dy1.
[0016] Preferably, the camera status includes the camera's position and camera orientation parameters.
[0017] Preferably, the camera's position includes latitude and longitude coordinates and altitude coordinates, with the latitude and longitude coordinates used as the camera's state coordinates; in the UE scene, a UE coordinate system is constructed using the altitude coordinates and the UE coordinates.
[0018] Preferably, the webGIS sends the camera status change of the camera to the UE scene every 30 frames.
[0019] Preferably, the camera status is sent via JSON data packets.
[0020] Preferably, the event bus system uses Delta encoding to process communication data in its synchronization protocol.
[0021] Beneficial effects
[0022] The advantages of this invention are:
[0023] 1. Coordinate transformation and alignment are achieved through a spatial control point mechanism. Each control point contains unique coordinates and associated features. By constructing a Delonix triangulation network to analyze the deviation of the webGIS camera status coordinates, the coordinate system transformation error can be reduced, and the accuracy of coordinate transformation between the two scenes can be greatly improved.
[0024] 2. Real-time synchronization of visual angles between two scenes is achieved through an event bus system. The synchronization protocol in the event bus system uses Delta encoding to process communication data, thereby achieving the goal of low latency. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the Deloni triangulation constructed according to the present invention;
[0026] Figure 2 This is a schematic diagram of one of the triangles in the Deloni triangulation of the present invention. Detailed Implementation
[0027] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.
[0028] This invention discloses a scene linkage method between a UE engine and a webGIS engine. When operating on a map in webGIS, an event bus system transmits the camera status from webGIS to the UE scene. The event bus system achieves real-time synchronization of visual angles between the two scenes, using Delta encoding as the synchronization protocol to achieve low latency. Specifically, the event bus system employs a Delta-encoded data stream compression algorithm, transmitting only changing values to achieve a data compression rate of 90%, reducing synchronization latency from the traditional 500ms to below 50ms, resulting in a performance improvement of over 10 times.
[0029] The event bus system establishes a bidirectional event channel between the UE engine and the webGIS engine, supporting events such as click picking, viewpoint changes, and feature updates. It achieves low-latency (<50ms) response through a publish-subscribe pattern. When a user clicks on the webGIS map, the event bus notifies the UE that the scene view has been positioned to the corresponding building. The core architecture of the event bus system comprises three key layers: the event source layer, the event network layer, and the event consumption layer. The event source layer is responsible for generating various events, such as ClickEvents generated by user clicks on the webGIS map, ViewportChangeEvents triggered by viewpoint changes, or FeatureUpdateEvents triggered by feature updates. These events enter the event network layer through standardized interfaces. This layer uses lightweight message queue technology to distribute and route events, ensuring reliable transmission in a distributed environment. The publish-subscribe pattern is the soul of the event bus system. When an event source generates an event, the system broadcasts the event to all processors subscribed to that event via EventBus.publish(). For example, when a user clicks on a building on the webGIS map, the system generates a ClickEvent containing the building's coordinates and ID and immediately publishes it to the event bus. All processors that have subscribed to ClickEvent (such as the UE view positioning module) will receive the event synchronously and trigger the corresponding processing logic.
[0030] The camera status in this embodiment includes the camera's position and orientation parameters. Furthermore, the camera's position includes latitude and longitude coordinates and altitude coordinates, with latitude and longitude coordinates used as the camera status coordinates. The camera's orientation parameters include yaw angle (Heading), pitch angle (Pitch), and roll angle (Roll). Specifically, Heading: the angle of rotation around the vertical axis, 0° for true north, rotating clockwise east (unit: radians); Pitch: the angle of rotation around the horizontal axis, defaulting to -90° (view from above), 0° for eye level, and positive values for view from below; Roll: the angle of rotation around the camera's front and rear axes, defaulting to 0°, with positive values for tilting to the right.
[0031] Camera status is sent via JSON data packets, including timestamps, camera location (latitude, longitude, and altitude), and camera orientation parameters (heading, pitch, and roll). After data synchronization is initiated, webGIS sends camera status changes to the user experience scene every 30 frames. Synchronization errors are controlled within 16ms through timestamp alignment.
[0032] The following is an example of the JSON data packet sent:
[0033] {"timestamp":"2023-10-25T14:30:00Z","position":{"x":116.3975,"y":39.9087,"z":50.0},"Orientation":{"Heading":"20","Pitch":"-45","Roll":
[0034] "-30"}}.
[0035] After receiving the data packet, the UE scene extracts the camera state coordinates from the camera state, calls the offset-based coordinate transformation algorithm to convert the camera state coordinates into UE coordinates in the UE scene, and then constructs the UE coordinate system.
[0036] In this embodiment, the coordinate transformation algorithm based on offset transformation is specifically as follows:
[0037] The first step is to extract coordinate points with the same name from the UE scene coordinates and the camera state coordinates as control points. For example, in the UE scene, the coordinates of the same name coordinate point are represented as (x1, y1), and in the camera state, the coordinates of the same name coordinate point are represented as (x2, y2). The table below shows the coordinate points with the same name in the UE and webGIS scenes.
[0038]
[0039] The second step involves creating a point matrix based on the control points in the UE scene, and simultaneously calculating the coordinate offsets of the UE scene coordinates and camera state coordinates corresponding to the control points, i.e., Dx1 = x2 - x1, Dy1 = y2 - y1. Then, a Delonix triangulation is constructed based on the point matrix and the coordinate offsets, as follows: Figure 1 As shown.
[0040] The third step is to use the camera state coordinates corresponding to the control point as the target point for spatial querying to obtain the triangle in which the target point is located in the constructed Deloni triangulation.
[0041] Step 4: Calculate the target offset based on the coordinates of the target point and the coordinates of the control points of the triangle corresponding to the target point. The formula for calculating the target offset is:
[0042]
[0043] Wherein, the coordinates of the target point are (x, y); the target offset is (Dx, Dy); and the coordinates of the three control points of the triangle corresponding to the target point are (x1-Dx1, y1-Dy1), (x2-Dx2, y2-Dy2), and (x3-Dx3, y3-Dy3); x 21 =x2-x1,x31 =x3-x1,y 21 =y2-y1,y 31 =y3-y1,Dx 21 =Dx2-Dx1,Dx 31 =Dx3-Dx1,Dy 21 =Dy2-Dy1,Dy 31 =Dy3-Dy1.
[0044] Step 5: Calculate the target point's offset position based on the target offset and use it as the UE coordinates, such as... Figure 2 P(x-Dx,y-Dy) is shown in the figure.
[0045] Coordinate transformation and alignment are achieved through a spatial control point mechanism. Each control point contains unique coordinates and associated features. By constructing a Delonix triangulation network to analyze the deviation of the webGIS camera status coordinates, the coordinate system transformation error can be reduced, specifically controlled within 0.1-0.3 meters, which greatly improves the accuracy of coordinate transformation between the two scenes.
[0046] After the coordinate transformation is complete, a UE coordinate system is constructed in the UE scene using height coordinates and UE coordinates. Then, the LOD control strategy is invoked to perform fast rendering in the UE scene. LOD technology determines the rendering precision based on the distance between the camera and the model: a lower precision simplified model is displayed when the distance is far, and a higher precision detailed model is loaded when the distance is close.
[0047] In WebGIS, two main refinement strategies are used: add (progressive addition) and replace (complete replacement). The add strategy continuously adds detailed elements as the viewpoint approaches, while the replace strategy directly switches to a complete model of different precision. In a UE scene, multiple versions of meshes are created for the same model, typically including high-poly, medium-poly, and low-poly levels. The system automatically switches between different levels of detail meshes based on the distance between the camera and the object. When the camera moves away, the system uses a low-precision model with fewer faces and vertices; when the camera moves closer, it switches back to a high-precision model.
[0048] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.
Claims
1. A method for scene linkage between a UE engine and a webGIS engine, characterized in that, When operating on the map in webGIS, the camera status in webGIS is transmitted to the UE scene through the event bus system. The UE scene extracts the camera status coordinates from the camera status and calls the coordinate transformation algorithm based on offset transformation to convert the camera status coordinates into UE coordinates in the UE scene, and then constructs the UE coordinate system. The Lod control strategy is invoked to perform fast rendering in the UE scene.
2. The method for scene linkage between a UE engine and a webGIS engine according to claim 1, characterized in that, The coordinate transformation algorithm based on offset transformation is as follows: The first step is to extract coordinate points with the same name from the coordinates of the UE scene and the camera status coordinates as control points; The second step is to create a dot matrix based on the control points in the UE scene, and at the same time calculate the coordinate offset of the UE scene coordinates and camera state coordinates corresponding to the control points, and construct a Deloni triangulation based on the dot matrix and coordinate offset. The third step is to use the camera state coordinates corresponding to the control point as the target point for spatial querying to obtain the triangle in the constructed Dillonian triangulation where the target point is located. Step 4: Calculate the target offset based on the coordinates of the target point and the coordinates of the control points of the triangle corresponding to the target point; Step 5: Calculate the position of the target point after the offset based on the target offset and use it as the UE coordinates.
3. The method for scene linkage between a UE engine and a webGIS engine according to claim 2, characterized in that, The formula for calculating the target offset is: Wherein, the coordinates of the target point are (x, y); the target offset is (Dx, Dy); and the coordinates of the three control points of the triangle corresponding to the target point are (x1-Dx1, y1-Dy1), (x2-Dx2, y2-Dy2), and (x3-Dx3, y3-Dy3); x 21 =x2-x1,x 31 =x3-x1,y 21 =y2-y1,y 31 =y3-y1,Dx 21 =Dx2-Dx1,Dx 31 =Dx3-Dx1,Dy 21 =Dy2-Dy1,Dy 31 =Dy3-Dy1.
4. The method for scene linkage between a UE engine and a webGIS engine according to claim 1, characterized in that, The camera status includes the camera's position and orientation parameters.
5. The method for scene linkage between a UE engine and a webGIS engine according to claim 4, characterized in that, The camera's position includes latitude and longitude coordinates and altitude coordinates, with the latitude and longitude coordinates serving as the camera's state coordinates; in the UE scene, a UE coordinate system is constructed using the altitude coordinates and UE coordinates.
6. A method for scene linkage between a UE engine and a webGIS engine according to claim 1 or 4, characterized in that, The webGIS sends the camera status change information to the UE scene every 30 frames.
7. The method for scene linkage between a UE engine and a webGIS engine according to claim 6, characterized in that, The camera status is sent via JSON data packets.
8. The method for scene linkage between a UE engine and a webGIS engine according to claim 1, characterized in that, The event bus system uses Delta encoding to process communication data in its synchronization protocol.