Take the project delivery practice based on UE game engine as an example
There are mainly the following processes:
1) Digital twin 3D scene construction and rendering
Digital twin 3D scene construction is a process of digital modeling and rendering of physical world scenes in digital space, and is an important part of digital twin technology. Digital twin scene construction includes requirements analysis, data collection, model construction, scene rendering, and optimization iterations.
Requirements analysis : Requirements analysis is the first and most important step in building a digital twin scene. It determines the goals, scope, objects and requirements of digital twin scene construction, as well as the corresponding visual accuracy level. The visual accuracy level refers to the visual similarity or difference between the digital twin scene and the physical world scene. It is usually divided into five levels, L1~L5, from low to high, indicating that the visual accuracy is from low to high. Different goals, scopes, objects, and needs may require different levels of visual precision to meet. For example, if you want to build a digital twin scene for urban planning or traffic simulation, then L1 level may be enough; if you want to build a digital twin scene for industrial design or education training, then L4 or L5 level may be more suitable.
Data acquisition : It is necessary to select appropriate data sources, production tools, rendering effects and interactive methods to build digital twin models and scenarios. Different visual precision levels may require different data sources, production tools, rendering effects and interactive methods to achieve. For example, if you want to build an L1-level digital twin scene, you may only need to generate a 3D map based on data sources such as satellite images, terrain data, and road networks; Cameras, sensor networks and other data sources are used to collect real-time data, and rendering techniques such as displacement maps and refraction effects are used to improve the sense of detail and dynamics, and to achieve free interaction with elements such as personnel and vehicles.
Model construction : The 3D model is an important part of the digital twin world, which can reflect the shape, structure, function and other characteristics of the physical world. At present, the commonly used 3D model production methods include BIM model, oblique photography and modeling in 3D software.
Scene rendering : Scene rendering in digital twins generally refers to the use of 3D modeling technology to construct a virtual reality scene, and achieve high-precision, high-fidelity, real-time rendering of the scene through the rendering engine, and at the same time integrate the data information in the real scene into the In the virtual scene, the monitoring and control of the real situation is realized. Before starting the scene construction, first analyze the style, theme, atmosphere, etc. of the scene you want to build, and find some reference pictures or similar items, then create a new project in the rendering engine, and set the basic parameters of the scene , such as viewing angle, lighting, post-processing, etc. Use scene management tools such as hierarchy, world outline, blueprint, etc. to organize and control your scene objects, and layout and place them in the viewport, and use terrain editor, procedural vegetation volume, etc. to create according to project needs and paint terrain and vegetation, and adjust their materials and parameters. Finally, use the lighting system, sky ball, fog effects, etc. to set and adjust the lighting and atmosphere of the scene, and optimize performance and effects.
Optimization iteration : Through data collection, analysis and feedback on real and simulated scenes, continuously improve product design, process design, engineering design, etc., and improve product performance, quality and efficiency. For example, you can replace or process assets, use high-quality models, textures and materials, improve art effects and performance indicators, use LOD, Cull Distance, Lightmap and other tools to optimize scenes, and optimize page interaction and visual design according to functional scenarios and user needs , improve user experience and satisfaction.
2) Digital twin data linkage and
fusion rendering of scene management data and scenes
Give an example of device tag data binding and weather, sky, light and environment system conditions to illustrate.
Equipment marking, data binding: Find the corresponding position and number of equipment from CAD or other reference drawings. Create a device-related POI point in UE, create an icon component and a number variable in the POI, use the corresponding device icon for the icon, and open the number variable to the instance to fill in freely, and place the device POI at the corresponding position in the scene and record it serial number. If there is a corresponding location of equipment in the model file, you can determine the location of the equipment in the scene by importing the model file, replace each equipment model with the equipment POI point, and record the corresponding equipment number. At the same time, create and click the POI in the device that needs to be clicked, and then send the device ID to the Web and highlight the icon, and the Web will display the corresponding device information.
Adjustment of weather, skylight environment and other systems : Use custom sky environment components to create different sky lighting effects, and the sky lighting effects show four different environmental effects in the morning, day, dusk, and night over time. The lighting simulation conforms to the scattering effect of the real atmospheric environment, and conforms to the influence of the latitude and longitude of the actual location on the scene. The time setting of the sky lighting environment can be selected to access the standard Beijing time data to realize the time and environment synchronization between the twin scene and the real world. Weather effects need to be carefully adjusted by scene effects, such as sunny days and rainy days. Create a wet rain effect on the scene material, and turn it on when needed. Considering that rain hits the surface of the model, the model accesses weather data from Web/API or other methods, for example, when it is sunny, the environment is clear, and the model's rain wetting effect is not enabled; when it is rainy, the sky is raining, and the model is enabled at the same time The wetness effect of rain.
Management of interactive scene shots and setting
scene management : layered management of scenes in different areas refers to displaying the scenes in the corresponding areas when they reach the corresponding areas. Using the scene manager can realize the management of different scenes. When switching from scene A to scene B, first use the scene manager to unload scene A, then use the scene manager to load scene B, after the loading is complete, transition from the current shot to the corresponding shot of scene B, and record the scene state.
Lens management : Create multiple different camera angles for different scenes (adjustment includes lens position, rotation, lens distance, whether to lock, etc.), set different numbers for different lenses, and switch between different angles of view according to user operations. For example, when viewing different viewing angles of a building, when the user clicks the button on the left side of the building, the Web sends a JSON data to the UE to switch the viewing angle to the left side of the building. After receiving the JSON data, the UE parses it, and then switches the viewing angle from the current position. Go to the corresponding perspective on the left side of the building.
3) Scenario publishing and system deployment
Web+UE interactive linkage and program packaging: use Web+UE communication components to embed corresponding web pages into UE, and display pages with visual charts and 3D twin scenes together. And do interactive linkage. After the UE program system is completed, the packaged program output is performed, and the output file is in EXE format. Copy the EXE file to the Windows computer, and then modify the WebURL, oblique photography model URL, TMS related URL, etc. we need through the configuration file of the program.
Client operating mode : Place the packaged client program on the corresponding computer, modify the relevant web page, tilt the model address, and directly open the program to run.
Cloud rendering mode : Place the packaged client program on the corresponding server and install the cloud rendering service. Set the corresponding parameters (IP address/port number), start the cloud rendering service, start the client program, and use other computers to open the corresponding address through a web browser to display the remote client screen.
The digital twin project delivery based on the game engine mainly involves the following roles:
PM/PD:
communicate with Party A to determine the requirements and provide prototype drawings;
determine the reference drawings for the rendering of each part (such as the UI style of the design and the scene style of the scene part) );
Follow up the project for communication;
Designer:
Design schemes and design drafts according to PM's needs\prototype drawings\reference;
make UI after design draft is finalized;
assist PM to provide reference pictures to the scene;
connect with the scene to control the consistency of 2D and 3D art effects;
Modeler:
Provide customized models according to scene editing requirements; (project modeling)
provide prefabricated models according to scene editing requirements; (asset library production)
Scene editing:
make scene atmosphere according to the art effect provided by PM and designer;
put forward model requirements for the model according to the scene content, and conduct docking and acceptance with it; connect
with TA to make various special effects;
make digital twin 3D scene;
and develop Match the functional requirements in the scene;
TA:
Provide special material effects, procedural generation, particle effects, tools to improve efficiency, etc. according to the needs of scene editing;
visual effects generated when interacting with development docking processing; (such as building demolition, dam discharge water flow, etc. need to be triggered by buttons Effect)
UE digital twin engineer:
conduct function development according to the scene produced by UE ground, the materials provided by the designer and the requirements of PM;
configure the interactive content in the scene;
package the project;
provide relevant technical support;
Front-end development engineer:
Communicate with customers on data format and situation;
cooperate with designers to design interactive methods in the screen;
data access;
interact with UE development for configuration;
communicate with other integrated systems (such as the collaborative system of East Station);