Method for determining the insolation of a point of a three-dimensional scene located at a geographical location
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-04
- Publication Date
- 2026-08-13
Smart Images
Figure FR2026050108_13082026_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE: Method for determining the sunlight at a point in a three-dimensional scene located at a geographical location
[0003] technical field
[0004] The present invention relates to a method for determining the solar exposure of a point in a three-dimensional scene located in a geographical location, and in particular in an urban environment.
[0005] State of the art
[0006] In urban planning, there is a need to be able to determine and simulate the sunlight received by an area in an urban environment, such as a ground surface, a roof, or a building facade. In bioclimatic architectural design, it is desirable to be able to determine the sunlight received by a building from the design stage, taking into account its intended position within its urban environment. It is also desirable to be able to determine and model the impact of a new construction on the sunlight received by surrounding buildings.
[0007] Several computer tools exist to address these needs. However, these tools remain complex to use, do not provide directly usable information, or remain imprecise, both with regard to the position of the area to be studied and the consideration of the sun's path throughout the year.
[0008] Existing solar irradiance simulation and solar impact modeling tools have several major limitations. They often rely on static simulations or theoretical calculations that do not allow the user to directly interact with the 3D model of the area under study. This limitation prevents the user from easily exploring different solar irradiance configurations in real time. Many tools use only simplified models or two-dimensional representations. Therefore, it is not possible to accurately determine shadows and complex solar interactions, particularly in dense urban environments or areas with irregularly shaped buildings.
[0009] Furthermore, most existing tools use standard geographic positioning values and do not incorporate flexible management of location data or local addresses, which limits their application in diverse contexts. It is therefore not possible to take into account specific solar parameters related to a precise geographic location.
[0010] Existing tools are not always capable of accounting for variations in sunlight throughout the year with sufficient granularity, which limits their usefulness for specific applications such as optimizing sunlight exposure or bioclimatic building design. Furthermore, seasonal adjustments, such as daylight saving time changes or equinoxes, are often poorly managed.
[0011] More generally, traditional solar simulation tools exhibit performance problems when attempting to model complex 3D environments. For example, calculations of shaded and sunlit surfaces can be slow or inaccurate, particularly when dealing with large areas or a high density of urban elements.
[0012] In addition, the use of certain advanced simulation tools requires technical expertise, and is therefore difficult for non-specialist users, such as architects or urban planners not trained in programming or simulation, to access.
[0013] It is therefore desirable to propose a method for determining the sunlight exposure at a given point, particularly in an urban environment, capable of taking into account the precise geographical location of that point, the accurate 3D morphology of its surroundings, and high-resolution sunlight data covering the entire year. It may also be desirable for this method to be implementable by non-specialists in programming or computer simulation.
[0014] Summary
[0015] Some embodiments relate to a method for determining the sunshine of a geographical point, the method comprising computer-implemented steps consisting of: displaying a three-dimensional scene of a geographical location on a display screen, receiving the position of a geographical point belonging to the scene and selected by a user; determining a solar path during a period, as seen from the selected point;generate a sunlight table for the selected point by a ray-casting process of shadows cast on the displayed scene, during the period, from positions of the sun in the solar path, the selected point of the scene being exposed to direct sunlight at a given instant, if a ray from the position of the sun at that instant does not encounter an obstacle in the scene, and to the shadow of another object in the scene otherwise, the sunlight table indicating for each instant of the period whether the selected point is directly illuminated by the sun or not; and following a selection by the user of an instant in the period, determine a position of the sun at the selected instant, and determine and display shadows of the scene as a function of the position of the sun at the selected instant and a morphology of the scene.;
[0016] This process enables detailed 3D modeling of the urban environment in real time, with dynamic solar simulation that can be based on the sun's exact position for each day of the year. This approach can offer increased accuracy in calculating shadows and sunlight, which is particularly beneficial for urban planning projects, bioclimatic design, and building energy performance calculations.
[0017] The user can more intuitively select a point in the displayed scene and thus more easily explore different sunlight configurations and optimize the design according to local conditions.
[0018] According to one embodiment, the process includes steps for generating the three-dimensional scene using open programming interfaces.
[0019] The implementation of open APIs (Application Programming Interfaces) such as OpenStreetMap and IGN DBTOPO ensures access to standardized and up-to-date geographic data, and better integration with other urban planning systems and analysis tools, facilitating the standardization of processes and interoperability between different tools used in urban design and management.
[0020] According to one embodiment, the point belonging to the scene is selected by the user using a pointing device in the displayed scene.
[0021] Thanks to user interaction via direct clicks on the surfaces of a 3D scene, the user can intuitively select a point within the scene. This interactive interface, based on mouse clicks in an intuitive 3D environment, is accessible even to non-specialist users, such as architects or urban planners. This user-friendly design simplifies system use and reduces barriers to entry for professionals who are not experts in simulation or programming. Unlike complex tools requiring advanced technical skills, this solution allows for wider adoption and faster learning. In one embodiment, the process includes a step of displaying the solar irradiance table, with the user selecting the specific time within the period using a pointing device within the displayed solar irradiance table.
[0022] Thanks to user interaction via a direct click within the sunlight table, users can intuitively select a time of year and directly visualize how shadows are distributed within the displayed scene. This allows users to easily explore different sunlight configurations and optimize the design based on local conditions. These features contribute to wider adoption and faster system learning.
[0023] According to one embodiment, the sunlight table indicates the times in the period corresponding to night, dawn and dusk seen from the selected point, and the times in the period when the selected point is in the shade and directly illuminated by the sun.
[0024] The user can thus select a moment knowing in advance whether the selected moment is directly illuminated by the sun or not.
[0025] According to one embodiment, the process includes steps of generating and displaying a heliodon centered on the selected point, the heliodon representing the solar path seen from the selected point during the period.
[0026] The user can thus visualize the position of the sun relative to the selected point throughout the year.
[0027] According to one embodiment, the process includes animation steps for the foliage of trees presented in the displayed scene as a function of the selected instant in the period.
[0028] The animation of tree foliage throughout the year gives the user a more realistic view of the scene.
[0029] According to one embodiment, the solar table is generated taking into account the presence of a tree likely to block the sun illuminating the selected point and a percentage of obstruction varying over time according to the development of the tree's foliage.
[0030] Taking into account the presence of trees allows for a more precise determination of the solar energy likely to be received by the selected point in the scene.
[0031] According to one embodiment, the process includes animation steps for deploying or retracting blinds or shutters presented in the displayed scene according to the selected moment in the period.
[0032] Animating the deployment of blinds throughout the year gives the user a more realistic view of the scene. According to one embodiment, the sunlight table is generated taking into account the presence of a blind and the definition of a period when the blind is deployed and obscures the selected point.
[0033] Taking into account the presence of blinds allows for a more precise determination of the solar energy likely to be received by the selected point in the scene.
[0034] According to one embodiment, the determination of the solar path during the period, as seen from the selected point, is carried out using open and standardized libraries and programming interfaces.
[0035] The implementation of open and standardized APIs (Application Programming Interfaces) such as Three.js and SunCalc, respectively for managing 3D models and simulating solar trajectories, enables fast and efficient calculations, even in urban environments with complex morphologies. Compared to longer and more expensive calculation methods, the interactive approach and real-time processing accelerate the production of results and reduce the overall design process time, allowing users to quickly test and adjust different configurations. Integrating such libraries and APIs also reduces the costs associated with developing and maintaining custom software.Because these tools are widely used and well documented, they offer a robust solution at a lower development cost, without requiring considerable resources to create proprietary tools or expensive custom solutions.
[0036] Embodiments may also relate to a system comprising a processor, memory, display screen, and user control interfaces, the processor being configured to execute program instructions stored in memory, the execution of program instructions by the processor implementing the previously defined process.
[0037] Brief description of the figures
[0038] The present invention will be better understood with the aid of the following description of exemplary embodiments with reference to the accompanying figures, in which identical reference symbols correspond to structurally and / or functionally identical or similar elements.
[0039] Figure 1 schematically represents a calculator implementing the process of determining the sunlight at a selected point in a 3D scene located at a geographical location, according to one embodiment. Figure 2 schematically represents, in perspective, an example of an urban environment and more specifically a building belonging to this urban environment.
[0040] Figure 3 schematically represents the steps in the process of determining the solar irradiance of a selected point, according to one embodiment. Figures 4A and 4B respectively represent a schematic perspective view of the building and a solar irradiance table relating to a selected point of the building, according to one embodiment.
[0041] Figures 5A and 5B respectively represent a schematic perspective view of the building and the solar irradiance table, with a point selected in the solar irradiance table, according to one embodiment,
[0042] Figures 6A and 6B respectively represent a schematic perspective view of the building and the solar exposure table, with another point selected from the solar exposure table, according to one embodiment,
[0043] Figure 7 represents solar irradiance values that can be calculated and displayed.
[0044] Figure 8 represents the solar radiation table for the selected point on the building, modified according to the shading produced by a tree, according to one embodiment,
[0045] Figure 9 represents the solar exposure table for the selected point of the building, modified according to the shading produced by a blind, according to one embodiment.
[0046] Detailed description
[0047] Figure 1 represents a computing unit (CU) implementing a method for determining the solar irradiance of a point in a three-dimensional scene located at a geographical location, according to one embodiment. The computing unit can be configured to execute instructions from a computer-readable medium to perform the functions or processes implementing this method. Thus, the computing unit can include a processor (PRC), one or more memory (MEM) units, and a system bus (SBS). The SBS provides an interface for the system components, including the MEM unit and the processor (PRC). The processor (PRC) can include any number of hardware components for processing data or signals or for executing computer code stored in the MEM unit.The PRC processor device may, for example, include a general-purpose processor, an application-specific processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a circuit containing processing components, a group of distributed processing components, a group of distributed computers configured for processing, or another programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described in this document. The processing device may also include computer-executable code that controls the operation of the programmable device.
[0048] The SBS system bus can be one of several types of bus structures that can be interconnected to a memory bus (with or without a memory controller), a peripheral bus, and / or a local bus using one of the various bus architectures. The MEM memory can include one or more data storage devices and / or computer code whose execution enables or facilitates the implementation of the solar irradiance determination process. The MEM memory can be connected to the PRC processor device (for example, via a circuit or any other wired, wireless, or network connection) and can include computer code for executing one or more processes implementing this method. The MEM memory can include non-volatile memory (NVM) (for example, read-only memory (ROM), programmable eraseable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.).and volatile memory (VM) (for example, random access memory (RAM)), or any other medium that can be used to carry or store desired program code in the form of instructions or data structures executable by a machine and accessible by a computer or other machine with a processor. A basic input / output software component (BIOS) ISW can be stored in non-volatile memory (NVM) and include basic routines that help transfer information between the elements of the computing unit (CU).
[0049] All or part of the implementation examples of the method for determining solar irradiance can be implemented as a computer program product (CPP) stored on a usable or readable transient or non-transient storage medium (e.g., a single medium or multiple media), such as non-volatile memory (NVM), which includes complex programming instructions (e.g., complex computer-readable program code) to cause the PRC processing device to execute the steps of this method. Thus, the computer-readable program code can include software instructions to implement the functionalities of the method examples when executed by the PRC processor.
[0050] The processing unit (CU) may also include an input / output interface (Ul) circuit. The Ul input / output interface can be configured to receive inputs and selections to be communicated to the processor (PRC) during instruction execution, for example, from a keyboard (KB), a pointing device (MS) such as a mouse, a touch surface, etc. These input devices can be connected to the processing device (PRC) via the Ul interface circuit coupled to the system bus (SBS). The Ul interface circuit can be configured to transmit an output, for example, to a display (DS), a video display unit (e.g., a liquid crystal display, LCD). The processing unit (CU) may also include an EMI connection interface circuit coupled to the system bus (SBS) and configured to connect to one or more external memories, for example, storing a database (DB).The computing unit CU may also include a communication interface circuit CMI coupled to the SBS system bus and implementing one or more communication protocols to communicate using an appropriate NT network with other systems, such as servers for example giving access to external databases.
[0051] Figure 2 schematically represents an image of a 3DS scene displayed on the DS display screen connected to the CU computing unit implementing the solar radiation determination process, according to one embodiment. The displayed 3DS scene may depict an urban environment including a building 1. Thus, the solar radiation reaching building 1 may be totally or partially obscured by other buildings during certain periods of the year. The urban environment model can be imported by the computing unit using software components that provide access to databases such as OpenStreetMap, IGN™ DBTOPO, Google™ Earth tiles, ESRI™, or other urban digital twin models, for example, generated using LiDAR sensors.
[0052] From the imported data, the urban environment model is rendered in three dimensions, for example, using the Three.js software library. This library generates a three-dimensional model in which the volumes of buildings and other urban and geographical elements are represented as surfaces, polygonal volumes, or more complex models, in order to precisely determine the areas of shade and direct sunlight across the entire 3D scene displayed on the DS screen. This approach ensures a faithful representation of the real environment and allows for the simulation of shadow effects with a high degree of accuracy. Three.js is a JavaScript library for creating and rendering interactive 3D graphics in a web browser, using WebGL™ software.This library allows you to manage 3D objects, lights, animations, and interactions, while also offering virtual reality (VR) and augmented reality (AR) capabilities. Commonly used for visualizations, games, and immersive experiences, it simplifies the development of high-performance and immersive 3D scenes. Other 3D viewers can also be used, such as Unity™, Autodesk™, Cesiumjs™, or ESRI™.
[0053] Figure 3 illustrates steps S1 to S14 of the solar irradiance determination process, according to one embodiment. Given the position and orientation of the urban environment as displayed on the screen, the calculation unit CU determines the geographical position of building 1 and the orientation of its facades as shown in the image displayed on the screen DS. The calculation unit CU allows the user to input appropriate commands, for example, using the pointing device MS and / or the keyboard KB, to rotate the urban environment displayed on the screen, for example, to show sides of building 1 not visible in Figure 2.
[0054] During a first step S1, the user designates a point SP on the image displayed on the screen DS, for example by moving a pointer PR displayed on the image (Figure 2) using the pointing device MS and by activating a control button, for example, on the pointing device MS. The point SP can, for example, be located on a visible face (facade or roof) of building 1 or around it. The calculation unit CU determines the geographical position of the point SP thus designated by the user. It can also determine the orientation of the face on which the selected point SP is located.
[0055] During step S2, illustrated by Figure 4A showing the 3DS scene and triggered by the selection of point SP, the calculation unit CU determines the sun's position SN for each day throughout the year, based on the geographical location of point SP and the orientation of the face to which that point belongs. This calculation is performed with a fine granularity, for example, with a step size between one hour and one minute, depending on the available computing and storage capacity. These positions can be calculated using components from a program library such as SunCalc. The sun's positions thus obtained are compiled into a heliodon HL, displayed on the DS screen in step S3 and positioned around point SP. The heliodon HL represents the sun's path over a year in the form of curves.During steps S4 and S5, the Cil calculation unit calculates the shadows cast on the displayed 3D scene throughout the year, based on the sun's position, using a ray-casting method such as Raycaster. The sun's position is expressed, for example, in azimuth and elevation. If a ray does not encounter an obstacle in the 3D scene, the corresponding point SP in the scene is exposed to direct sunlight; otherwise, it is in the shadow of another object in the scene. The results of these calculations are compiled in a solar exposure table SE, which is displayed, for example, in step S6 alongside the 3DS scene. Figure 4B shows an example of a solar exposure table SE as displayed on the DS screen. The example SE table shown in figure 4B presents on the x-axis the days of the year indicated by the months of the year from "JAN" for January to "DEC" for December and on the y-axis the hours of the day from "Oh" to "24h".The example SE table includes a gray area SH covering the days and times when the sun illuminates the 3D scene, light gray areas DW and TW at the top and bottom edges of SH indicating dawn and dusk respectively, and a central dark gray area DI covering the periods when the designated point SP is directly illuminated by the sun. The breaks in March and October appearing in areas DI, SH, DW, and TW correspond to the days of the switch to and from daylight saving time. Areas outside the gray zones correspond to nighttime. The SE table can be generated using the D3.js software library, which allows for the creation of interactive and dynamic data visualizations. This library uses web standards such as SVG, HTML, and CSS to bind data to DOM elements and apply transformations to them. The SE table is therefore displayed as an interactive element.By clicking on a point in the displayed SE table, the position of that point is recorded to identify a specific moment (day and time) in the year. From this designated moment, the sunlight and shadow conditions of the 3DS scene are recalculated and displayed according to the sun's position at that moment, for example using the Raycaster ray-casting method.
[0056] In step S7, illustrated in Figure 5B or 6B, the user designates a point STP in the SE table using the PT pointer controlled by the MS pointing device. In step S10, the CU calculation unit determines the time (day of the year and hour) DT corresponding to the STP point designated by the user in the SE table. In steps S8 and S9, the CU calculation unit updates the time DT to be considered and determines the position of the sun at time DT, using the heliodon HL or, for example, an ephemeris table. In steps S11 to S13, the CU calculation unit determines and displays an arrow SA indicating the direction of the sun SN from the point SP designated in the 3DS scene, and displays a symbol representing the sun SN at the end of the arrow SA (Figure 5A or 6A). At step S14, the Cil computing unit determines and displays the shadows BS of the scene as a function of the direction of the sun SN determined at step S9.
[0057] In the example in Figure 5A, the user selected the time "2:30 PM on April 20th" from the SE table. The side of building 1 where the selected point SP is located is sunny. In the example in Figure 6A, the user selected the time "9:00 AM on September 27th" from the SE table. The side of building 1 where the selected point SP is located is in the shade.
[0058] According to an embodiment illustrated in Figure 7, the calculation unit CU is also configured to calculate and display the number of hours of direct sunlight for the selected point SP, and the total number of hours of sunlight for the geographic point where point SP is located (without taking into account shadows cast on point SP). These numbers YP, EP, WP can be calculated over the year (WP), and / or during the summer period (EP) and / or during the winter period (WP). The calculation unit CU can also calculate and display a percentage of direct sunlight for the selected point SP relative to the total number of hours of sunlight, over the year (YP) and / or during the summer period (EP) and / or during the winter period (WP).
[0059] Figures 8 and 9 illustrate steps S4 and S11 in particular. In these steps, elements of the 3DS scene, such as trees, blinds, or shutters, are taken into account to determine the SE table. In the case of a deciduous TR tree (Figure 8), several periods of the year P1, P2, P3, P4, P5 are considered and associated with an aspect TA1, TA2, TA3 of the TR tree, representative of the tree's leaf density / color. When an STP point is designated in the SE table in step S10, the images of the trees presented in the 3DS scene are updated in steps S4 and S11 according to the period P1-P4 to which the designated STP point belongs and the tree's aspect TA1, TA2, TA3 at that period.
[0060] Furthermore, each of the year periods P1, P2, P3, P4, and P5 can be associated with a percentage of shade. Thus, during periods P1 and P5 (winter), the tree has no leaves. The shade percentage of tree TR can be set to 0. During periods P2 and P4 (spring and autumn), tree TR does not have all its leaves. The shade percentage of tree TR can be set to 50%. During period P3 (summer), the tree has all its leaves. The shade percentage of tree TR can be set to a value between 70% and 100%, depending on the tree species. If the point designated SP can be obscured by a tree during certain periods of the year, the SE table can be updated taking into account the percentages of obscuration associated with each of the periods P1-P5. In the case of a blind ST (figure 9), several periods of the year P11, P12, P13, are considered.During periods P11 and P13, the ST blind is considered to be retracted and therefore produces no shadows. During period P12, the ST blind is considered to be extended. When an STP point is designated in the SE table at step S10, the blind images appearing in the 3DS scene are updated at steps S4 and S11 according to the period P11-P13 to which the designated STP point belongs and the extended / retracted state of the ST blind at that time.
[0061] In addition, if a blind ST can obscure the designated point SP when deployed, the SE table can be updated taking into account the shadow cast by the blind ST on the point SP during the period P12.
[0062] The process just described has numerous applications. For example, it can be implemented in sustainable urban planning projects to analyze the impact of sunlight on existing or planned neighborhoods and buildings. In urban regeneration, for instance, this process allows for modeling the distribution of shade and sunlight on different types of buildings, thereby optimizing the design of facades, public spaces, and green areas. It can thus maximize solar gain for buildings while minimizing the negative impact of shadows on the urban environment, taking into account the terrain's geometry and surrounding infrastructure.
[0063] In the field of bioclimatic architecture, this process allows architects and designers to precisely define the orientation of buildings, windows, and other architectural elements to optimize solar gain and reduce heating and cooling needs. For example, when designing a new building, the process makes it possible to test different structural configurations, orientations, and the positioning of facades and windows to maximize solar exposure during the winter and minimize it in the summer, based on thermal requirements and energy efficiency strategies. By simulating solar impacts on different facades, the process allows for testing the effectiveness of solutions such as solar shading, blinds, shutters, or glazing films, adjusting their positioning to optimize energy efficiency throughout the year.
[0064] During the construction of new housing complexes or residential developments, this method can be used to simulate sunlight exposure on different plots of land and on proposed buildings. This makes it possible to guarantee optimal thermal comfort for future residents by analyzing the impact of building volumes on direct and indirect sunlight, while taking into account local urban planning regulations and specific geographical conditions. The method can also be used to determine the best areas for installing solar panels on roofs or building facades. By simulating the sun's path throughout the year, the method calculates areas with the greatest potential for direct sunlight, in order to maximize solar energy production, while considering the urban environment and shadows cast by other architectural elements.
[0065] The process can also be used to plan vegetation and public spaces in cities. By modeling shade and sunlit areas, urban planners can determine where to plant trees or create outdoor recreational spaces. This optimizes residents' comfort by creating shaded areas during the summer and avoiding overly shaded areas that could negatively impact the urban environment or agricultural spaces.
[0066] In the context of combating climate change, this method can be used to assess the long-term effects of climate variations on sunlight. By modeling the impact of climate change on sunlight over decades, urban planners and architects can anticipate the adjustments needed to make cities more resilient to changing solar conditions, whether for renewable energy management or green space planning.
[0067] The method can also be used to determine the best areas for installing solar panels on roofs or building facades. By simulating the sun's path throughout the year on roofs, facades, or other available surfaces, the method makes it possible to determine the areas with the greatest potential for direct sunlight, thus maximizing solar energy production, while taking into account the urban environment and shadows cast by architectural elements.
[0068] It will be readily apparent to those skilled in the art that the present invention is susceptible to various embodiments and applications. In particular, the invention is not limited to selecting a point by clicking the MS pointing device in a three-dimensional scene. For example, such a point can be selected by directly entering GPS coordinates or by using another location application such as Google Maps, Here Maps, or a custom database. Thus, the user can manually define a point on an interactive map or select a position from a list of predefined coordinates. It is also possible to define an arbitrary starting point within a closed environment (for example, a restricted space such as a neighborhood or a building) and to integrate a real-time georeferenced element service (for example, data from IoT sensors located at the site).
[0069] To obtain the solar path throughout the year, other libraries or solar calculation methods can be used, such as PyEphem or Astral (Python™). It is also possible to use publicly available astronomical equations. The solar path can be defined in a weather file in EPW format ("EnergyPlus™ Weather file"), a file format containing climate data used primarily in building energy simulation software, such as EnergyPlus™, DesignBuilder, Autodesk™, Graitec™ Archiwizard, Rhino, or TRNSYS™.
[0070] It is also unnecessary to use precise data concerning the sun's path as seen from a geographical point. Indeed, the process as described above can be implemented using approximate data based on simplified formulas specific to a local context or time of year, without using an external library. It is also possible to use only average durations of solar exposure.
[0071] It is also unnecessary to display a graphic heliodon superimposed on the displayed scene. Furthermore, other representations of solar behavior can be used, such as a table of hourly data or a simplified 2D view.
[0072] Urban data can be obtained from other sources such as GIS files (Shapefiles, GeoJSON) or proprietary geospatial databases. The generated 3D volumes can also be replaced by 2D maps, 2D contours, or projected orthophotos, with static or dynamic shading areas to analyze sunlight without recreating a 3D scene. Urban morphology can also be generated manually by positioning built volumes, or from user data (such as sketches or manual plans). The displayed 3D scene can also be simplified by showing only the major (taller) obstacles and using a method such as a solar mask diagram or volumetric simplification.
[0073] Other software libraries besides Three.js can be used, such as a 3D rendering engine like Babylon.js or Unity WebGL™, or a native engine like WebGPU. Alternatively, WebGL™ can be replaced by SVG or Canvas for simplified rendering. It's also possible to use a proprietary or open-source viewer to simplify 3D display (for example, by rendering only critical elements like sunbeams and shadows). A 3D viewer isn't even necessary. It can be replaced by a 2D system that simulates spatial interactions as shadows projected onto 2D maps or plans.
Claims
DEMANDS 1. A method for determining the solar irradiance at a geographical point, the method comprising computer-implemented steps and consisting of: display on a display screen (DS) a three-dimensional scene (3DS) of a geographical location, receive the position (SP) of a point belonging to the scene and selected by a user; determine a solar path (HL) during a period, as seen from the selected point; generate a solar irradiance (SI) table of the selected point by a ray-casting method of the shadows cast on the displayed scene, during the period, based on the sun's positions in the solar path, the selected point of the scene being exposed to direct sunlight at a given instant, if a ray from the sun's position at that instant does not encounter an obstacle in the scene, and to the shadow of another object in the scene otherwise, the solar irradiance table indicating for each instant of the period whether the selected point is directly illuminated by the sun or not; and Following a user selection of a time point (STP) within the period, determine a sun position (SN) at the selected time, and determine and display shadows (BS) of the scene based on the sun position at the selected time and a scene morphology.
2. Method according to claim 1, comprising steps of generating the scene (3DS) in three dimensions using open programming interfaces.
3. A method according to any one of claims 1 and 2, wherein the point (SP) belonging to the scene is selected by the user using a pointing device (MS) in the displayed scene (3DS).
4. A method according to any one of claims 1 to 3, comprising a step of displaying the sunshine table (SE), the time of the period being selected by the user using a pointing device (MS) in the displayed sunshine table.
5. A method according to any one of claims 1 to 4, wherein the sunlight table (SE) indicates the times in the period corresponding to night, dawn (DW) and dusk (TW) seen from the selected point (SP), and the times (SH, DI) in the period when the selected point is in the shade and directly illuminated by the sun.
6. A method according to any one of claims 1 to 5, comprising steps of generating and displaying a heliodon (HL) centered on the selected point, the heliodon representing the solar path seen from the selected point (SP) during the period.
7. A method according to any one of claims 1 to 6, comprising animation steps of the foliage (TA1, TA2, TA3) of trees (TR) presented in the displayed scene (3DS) as a function of the selected time (STP) in the period.
8. Method according to claim 7, wherein the sunlight table (SE) is generated taking into account the presence of a tree (TR) capable of occulting the sun illuminating the selected point (SP) and a percentage of occultation varying over time according to the development of the tree's foliage.
9. Method according to any one of claims 1 to 8, comprising animation steps for deploying or retracting blinds (ST) or shutters presented in the displayed scene (3DS) as a function of the selected time (STP) in the period.
10. Method according to claim 9, wherein the sunlight table (SE) is generated taking into account the presence of a blind (ST) and the definition of a period (P12) in which the blind is deployed and obscures the selected point (SP).
11. A method according to any one of claims 1 to 10, wherein the determination of the solar course (HL) during the period, seen from the selected point (SP) is carried out using open and standardized libraries and programming interfaces.
12. System comprising a processor (PRC), a memory (MEM), a display screen (DS), and user control interfaces (KB, MS), the processor being configured to execute program instructions stored in memory, the execution of program instructions by the processor implementing the method according to any one of claims 1 to 11.