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EP-4290463-B1 - METHOD FOR VISUALISING A 3D INFRASTRUCTURE DESIGN MODEL IN A PLANAR COORDINATE SYSTEM ON AN ELLIPSOID

EP4290463B1EP 4290463 B1EP4290463 B1EP 4290463B1EP-4290463-B1

Inventors

  • Vesanen, Juha

Dates

Publication Date
20260506
Application Date
20230609

Claims (15)

  1. A computer implemented method (700) for visualising a 3D infrastructure model on an ellipsoid, comprising; selecting (70) at least one 3D infrastructure model from a group of 3D infrastructure models, wherein the at least one 3D infrastructure model is obtained from one of an infrastructure design tool and a building design tool, or is a point cloud captured with a 3D scanner, wherein the 3D infrastructure model is defined in planar coordinates; storing (71), by a processor of a computer, original centre-points of the selected 3D infrastructure models; translating (72), by the processor, said 3D infrastructure models to move the centre-points of said 3D infrastructure models at the origin in planar cartesian coordinates of said 3D infrastructure models, correspondingly; determining (73), by the processor, a camera target point (26) in ellipsoid cartographic coordinates to a common centre-point of said 3D infrastructure models in the ellipsoid cartographic coordinates; converting (74), by the processor, the camera target point (26) from the ellipsoid cartographic coordinates to the planar cartesian coordinates; calculating (75), by the processor, unit axes in the planar cartesian coordinates; converting (76), by the processor, the unit axes to the ellipsoid cartesian coordinates; creating (77), by the processor, a reference frame (40) using the camera target point (26) in the ellipsoid cartesian coordinates and the unit axes; transforming (78), by the processor, said 3D infrastructure models on the ellipsoid using the reference frame (40) and the original non-translated centre-points of said 3D models; and drawing (79), by the processor, said 3D infrastructure models on a graphics display.
  2. A method according to claim 1 wherein the ellipsoid is a WGS84 ellipsoid.
  3. A method according to any preceding claim wherein said camera target point (26) is calculated by interpolating between an intersection point of a camera forward vector (32) and the ellipsoid surface (21) and a previous camera target point depending on the camera tilt angle with respect to a normal of the ellipsoid surface (21) at a camera position.
  4. A method according to any preceding claim wherein the determining of said camera target point (26) is done by calculating the intersection point of a camera forward vector (32) and the ellipsoid surface (21); and if the camera forward vector (32) does not intersect with the ellipsoid surface (21), then setting the camera target point (26) equal to the previous camera target point.
  5. A method according to any preceding claim wherein the interpolation factor is corrected using a S-curve such as a sigmoid curve or a smoothstep curve.
  6. An apparatus comprising a graphic display; at least one processor connected to the graphic display; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: visualising at least one 3D infrastructure model on an ellipsoid, comprising means for; selecting (70) at least one 3D infrastructure model from a group of 3D infrastructure models, wherein the at least one 3D infrastructure model is obtained from one of an infrastructure design tool and a building design tool, or is a point cloud captured with a 3D scanner, wherein the 3D infrastructure model is defined in planar coordinates; storing (71) original centre-points of the selected 3D infrastructure models; translating (72) said 3D infrastructure models to move the centre-points of said 3D infrastructure models at the origin in planar cartesian coordinates of said 3D infrastructure models, correspondingly; determining (73) a camera target point (26) in ellipsoid cartographic coordinates to a common centre-point of said 3D infrastructure models in the ellipsoid cartographic coordinates; converting (74) the camera target point from the ellipsoid cartographic coordinates to planar cartesian coordinates; calculating (75) unit axes in the planar coordinate system; converting (76) the unit axes to the ellipsoid cartesian coordinates; creating (77) a reference frame (40) using the camera target point (26) in the ellipsoid cartesian coordinates and the unit axes; transforming (78) said 3D infrastructure models on the ellipsoid using the reference frame (40) and the original non-translated centre-points of said 3D models; and drawing (79) said 3D infrastructure models on a graphic display.
  7. An apparatus according to claim 6 wherein the ellipsoid is a WGS84 ellipsoid.
  8. An apparatus according to any of the claims 6-7 wherein the means for calculating the said camera target point (26) comprise interpolating said camera target point (26) between an intersection point of a camera forward vector (32) and the ellipsoid surface (21) and a previous camera target point depending on a camera tilt angle with respect to a normal of the ellipsoid surface (21) at a camera position.
  9. An apparatus according to any of the claims 6-8 wherein the means for determining said camera target point (26) comprise calculating the intersection point of the camera forward vector (32) and the ellipsoid surface (21); and if the camera forward vector (32) does not intersect with the ellipsoid surface (21), then setting the camera target point (26) equal to the previous camera target point.
  10. An apparatus according to any of the claims 6-9 comprising means to correct the camera tilt angle using a S-curve such as a sigmoid curve or a smoothstep curve.
  11. A computer program comprising instructions stored thereon which, when the program is executed by a computer, cause the computer to carry out steps for visualising a 3D infrastructure model on an ellipsoid, comprising at least the following: selecting (70) at least one 3D infrastructure model from a group of 3D infrastructure models, wherein the at least one 3D infrastructure model is obtained from one of an infrastructure design tool and a building design tool, or is a point cloud captured with a 3D scanner, wherein the 3D infrastructure model is defined in planar coordinates; storing (71) original centre-points of the selected 3D infrastructure models; translating (72) said 3D infrastructure models to move the centre-points of the said 3D infrastructure models at the origin in planar cartesian coordinates of said 3D infrastructure models, correspondingly; determining (73) the camera target point in ellipsoid cartographic coordinates to a common centre-point of said 3D infrastructure models in the ellipsoid cartographic coordinates; converting (74) the camera target point from ellipsoid the cartographic coordinates to the planar cartesian coordinates; calculating (75) unit axes in the planar coordinate system; converting (76) the unit axes to ellipsoid cartesian coordinates; creating (77) a reference frame (40) using the camera target point (26) in the ellipsoid cartesian coordinates and the unit axes; transforming (78) said 3D infrastructure models on the ellipsoid using the reference frame and the original non-translated centre-points of said 3D infrastructure models; and drawing (79) said 3D infrastructure models on a graphic display.
  12. A computer program according to claim 11 wherein the ellipsoid is a WGS84 ellipsoid.
  13. A computer program according to any of the claims 11-12 wherein said camera target point (26) is calculated by interpolating between an intersection point of a camera forward vector (32) and the ellipsoid surface (21) and a previous camera target point depending on a camera tilt angle with respect to a normal of the ellipsoid surface (21) at a camera position.
  14. A computer program according to any of the claims 11-13 wherein the determining of said camera target point (26) is done by calculating the intersection point of the camera forward vector (32) and the ellipsoid surface (21); and if the camera forward vector (32) does not intersect with the ellipsoid surface (21) , then setting the camera target point (26) equal to the previous camera target point.
  15. A computer program according to claims 11-14 wherein the camera tilt angle is corrected using a S-curve such as a sigmoid curve or a smoothstep curve.

Description

FIELD OF THE INVENTION The present invention relates to computer graphics, especially to visualisation of three-dimensional models/designs on an ellipsoidal coordinate system such as World Geodetic System (WGS). BACKGROUND OF THE INVENTION Three-dimensional (3D) visualisation is an important developing computing technology essential for many specific industries, including construction, infrastructure building and design. The present invention relates to visualisation of 3D infrastructure design models originating from various design processes and utilising computer graphics visualise such 3D infrastructure design models on an ellipsoid using an ellipsoidal coordinate system such as the WGS84. Patent application US2022/076503A1 discloses a method for visualizing a three-dimensional model in an interactive editing workflow. BRIEF DESCRIPTION OF THE INVENTION An object of the present invention to provide a method and an apparatus for implementing the method so as to overcome the above problems. The objects of the invention are achieved by a method and an arrangement which are characterized by what is stated in the independent claims. The preferred embodiments of the invention are disclosed in the dependent claims. The invention is based on the idea carrying out transformations of 3D infrastructure design models of objects such as models of buildings or infrastructure or some other object, which are typically designed in planar coordinate systems i.e., having axis orthogonal against each other. Drawing 3D infrastructure design models, especially with substantial dimensions, on an ellipsoid coordinate system such as the WGS can cause inaccuracies when multiple 3D infrastructure design models are drawn. An advantage of the method and arrangement of the invention is that multiple 3D infrastructure design models can be drawn in the same view accurately. The 3D infrastructure design models may be originally designed in different planar coordinate systems. They may be designed e.g. by Computer Aided Design tools used in different fields of technology such as infrastructure design or building design or they might be point clouds captured with 3D scanners from real environments. For example, each country or city might utilize many different planar coordinate systems in their design processes. There are large databases available of such coordinate systems, for example one originally created by European Petroleum Survey Group (EPSG). Correct visualisation of multiple objects is essential for building industry, which by nature needs to integrate design from multiple sources. Furthermore, the 3D infrastructure design models used for designing an infrastructure project typically includes 3D infrastructure design models in very different scales. BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which: Figures 1a, 1b and 1c illustrate coordinate systems;Figures 2a and 2b is illustrate a camera view on the surface on an ellipsoid;Figure 2c illustrates a situation when a camera forward vector is pointed above horizon of an ellipsoid;Figure 3 illustrates 3D infrastructure design models of objects and their translated versions in their planar cartesian coordinates;Figure 4 illustrates 3D infrastructure design models of objects and placed on the surface of an ellipsoid;Figure 5 illustrates a reference frame place on the surface of an ellipsoid;Figure 6 illustrates an S-curve, which may be used in correcting the camera target point;Figure 7 illustrates a view with exemplary 3D infrastructure design models on the surface of the Earth created by different kinds of tools and methods: Figure 8 illustrates a process flow diagram illustrating an embodiment of a method for visualising a 3D infrastructure design model in a planar coordinate system on an ellipsoid;Figure 9 illustrates a block diagram of an example computing apparatus in accordance with various embodiments; DETAILED DESCRIPTION OF THE INVENTION In the following, different exemplifying embodiments will be described using, as an example of the method for visualising of three-dimensional models/designs on an ellipsoidal coordinate system. Figure 1a is illustrating an ellipsoid 20 with ellipsoidal cartographic coordinated system with lines showing longitudes 11 and latitudes 12. Figure 1b is illustrating an ellipsoid 20 with an ellipsoidal cartesian coordinate system, wherein origin of the coordinate system is located at center 13 of the ellipsoid 20. Earth-centered, Earth-fixed coordinate system (ECEF) is an example of a cartesian coordinate system that represents locations in vicinity of the Earth (including its surface, interior, atmosphere, and surrounding outer space) as x, y, and z measurements from its center of mass. The z-axis is in the direction of the rotational axis of the ellipsoid of revolution, Figure 1c illustrates a planar coordinate s