English Version.
Fourteen and ninety-five dollars is the current price of a circuit on iRacing. Is it a high or reasonable price? Well, I would say that, like everything, it depends on how you analyze it. What is clear is that it is on circuits where we are going to spend the most on this simulator, because although in cars you can focus on some classes and not leave them for a long time, the list of circuits in a series varies, so facing a season with some regularity means having a good part of them, even more so if you race on oval and road. The objective of this article is not, however, to talk about what it costs to run in iRacing, what we will do is focus on the 3D Laser Scanner systems to understand what they are and how they are used to create the simulation circuits in which we race.
Fans of simracing and motorsports in general already know, or at least have heard, that the circuits of the latest generation simulators are created with Laser Scanner (hereinafter, LE) technology. In reality, it is not that they are created “with”, but from the points obtained with this type of equipment. That is, the LE is used to perform the 3D topographic survey of the circuit.
Topography and cartography engineers have been measuring circuits for decades, only before they did it with other topographic equipment, because the need to have precise technical plans of the tracks is not new, it has been and is a need for professional competition teams to study the routes in detail and improve times.
Before Laser Scanners…
Before current 3D simulation systems, paper circuit plans and/or 2D computer systems were used to analyze the layouts. In fact, systems similar to raceoptimal are still used today to carry out this type of studies, but obviously the current systems are much more complete. However, none of this has value if it is not based on an adequate geometric representation of the circuit.
The LEs are nothing more than an evolution in the measurement technique. Before, topography engineers used theodolites and levels, then total stations and followed by topographic GPS equipment, and now the trend is LE. Traditional methods were very invasive and involved the total or partial paralysis of the circuit activity, since the presence of the surveying team for several days or weeks was necessary, depending on the circuit and project requirements. Building an entire 3 km circuit could take several weeks of full-time work. But it was what there was, and professional racing teams fed data into their studies and simulation systems with topographical surveys of this type, because for them it was (and is) critical to have reliable data.
This type of topographic surveys, although extremely precise, millimetric, were still a discrete model of reality, in the sense of non-continuous. The topography engineer decided which points to measure and which to lift the elements of the circuit. When you use topographic equipment of this type to measure, for example, a wall, or the runway edge line, you select the necessary points to trace its geometry, but no more. You do not measure one point every centimeter, nor a thousand points to draw an arc, you discretize, because it is not strictly necessary and because otherwise you would not finish even in ten years.
And this is precisely the main reason why LE systems have prevailed: the recording time is substantially reduced, on the one hand, and practically continuous surveys are obtained, on the other. Furthermore, previously the elements and spaces around the track, the escape areas, fences, walls, etc., were “invented” and modeled based on cartographic data or photographs of the surroundings, while now the LE also measures them, providing in the same sweep all the important data for the survey of the circuit in its entirety, not only the track itself. And this is also important, because these peripheral elements often function as visual reference elements for the pilots. To the extent that these elements are also rigorously located, we will be providing a more complete and faithful experience to reality.
However, if we are told that a circuit is surveyed with LE, we do not have to directly deduce that the absolute topographical precision obtained must be very high and better than those of “traditional” methods. We will have, yes, more points, but not necessarily better. Some simulators are selling work with LE as a claim, and we will see that, in part and in some cases, they are very sensational advertisements. But not because the LE are not very high-performance devices, which they are, but because the results of a topographic survey with LE, the positional precision of the points obtained, depend on several factors, distance, methodological and the complementary systems used together with the LE, and not only on the LE itself. In the end, as in everything, the results depend on what technology we use, but, above all, on how we apply it. We will also go into analyzing it later.
The word laser is the acronym in English for light by induced emission of radiation (Light Amplification by Stimulated Emission of Radiation). The first operational laser was demonstrated in May 1960 by Theodore Maiman at Hughes Research Laboratories. Since then they have been developed and perfected, and serve a multitude of sciences and professional fields. One of these fields is, as we have seen, that of measurement in Topographic Engineering.
The two university degrees that in Spain are specialized in the use of LE as measurement tools are the Technical Engineer in Geomatics and Topography (http://www.coit-topografia.es/) and the higher degree of this, the Higher Engineer in Topography, Geodesy and Cartography (http://www.topografia.upm.es/portal/site/ETSITopografia). Of course, they are not the only professionals who use this equipment, but they are undoubtedly the most potentially qualified due to their curricular training to do it correctly, controlling the methodology, guaranteeing the standard precision required in each project and combining these techniques with complementary measurement and positioning systems to adjust and georeference the measured set.
In the videos that iRacing has posted on its website to explain how they have used this technology to build the circuits, typically topographic material appears. The methodology applied is pure and simple topography: polygonal routes and linking techniques that allow maintaining the control and geometric overlap necessary to a) cover the entire circuit with successive stations, and b) be able to georeference all the shots taken. The LE seen in those iRacing videos is from the brand Leica, a multinational manufacturer of topographic equipment through its Leica group Geosystem. The Trimble brand also has this type of equipment, for example its TrimbleTX8 Scanner, and the brand FARO is also worth mentioning. There are other houses, but perhaps these three are the most important in this area.
Operation of a LE
But, , how does an LE operate? What the internal hardware of the LE does, basically, is launch a wave, a laser beam, and measure the time it takes to return to the equipment. It has, among others, optical-electronic systems for beam emission and reception, control of the angular positions of the equipment and processing of the recorded data (I link several videos at the end that explain it). As the device knows in a very precise way the characteristics of that ray, the speed at which it travels through the air, the time it takes to do so and also the environmental conditions, since it has internal sensors that measure these values, with all this calculates the distance at which that object or obstacle is that caused the bounce of the wave.
This, together with the fact that the equipment controls at all times the relative geometry of the emitted rays, vertical and horizontal angles of each of those signals that leave and enter, allows the system to assign XYZ coordinates to the records obtained, which are, in short, points in 3D space located around the LE.
In reality, the LE does not launch a wave pulse, but hundreds of thousands per second, enough to obtain the required resolutions and averages. You will get an idea that the issue is much more complex than all this, that there are time measurement scanners and others called triangulation, depending on how they measure distances, and that the first, in turn, are grouped into lasers by time of flight or by phase comparison, each with its advantages and disadvantages and therefore intended for different objectives and requirements. In short, different developments within the same technology that we group for simplicity as LE. Obviously, we will not go into all this because it is “a different story.”
It should be noted, however, that not all LEs work with the same resolutions and qualities, nor do they have the same distance ranges. What's more, the same LE equipment allows you to select different ranges of resolution and quality, since in some cases we will need “very fine” results and in others we will not. Resolution and Quality are the two most important parameters in a LE: Resolution, is the distance between points, which in turn depends on the distance at which the different objects are with respect to the position of the LE. That is, for the same shooting resolution, the elements closest to the LE will be represented by a denser cloud of points. The Quality, is the number of times that the LE will measure each point, since not a single measurement is made but several, with the objective of averaging and obtaining the most probable distance value for each point. In turn, LEs can also be classified by their scope. There are short range ones, for measuring caves, installations or interior buildings, designed for maximum distances of 30-40 m, others for medium range distances, up to 120 m and others long range, normally over 350 m. There are longer ranges, to carry out surveys from aircraft, but we will not go into these.
Most of the latest generation LEs are capable of obtaining up to 1,000,000 pts/sec. Yes, you read that right, a million points per second. And that's not all, because c still obtains the XYZ coordinates of each point with precisions <1 cm. In addition to the The cloud of points obtained, even though it is an unstructured set, because it is so dense, forms an image that allows the shape and texture of the objects taken to be interpreted with some clarity. On the other hand, some LE equipment has a built-in internal camera that allows each point to be assigned a color in the RGB system. This significantly improves the analysis capacity of the point cloud, since the cloud at certain zooms is shown as a photograph of the measured space.
After carrying out the survey of a circuit with a LE, what we obtain is simply a cloud of points that serves to identify the measured elements in the cabinet. Based on this information, which is not yet a surface or a structural element per se, just points arranged in space, we must start working to finally obtain a 3D model.
The detail of the following images shows in “A” a cloud of mono-color points, with a low resolution since the spaces between scans and the distances between point and point can be clearly seen.
In “B” and in the image above, the one of the track section, we have examples of shots with LE where the points contain the aforementioned reflectance value, which allows us to distinguish the different textures: it does not provide a photographic image, but it does allow us to better identify the elements than in “A”.
In the following image, “C”, we are in the case in which the LE incorporates an internal camera that assigns the RGB color to each point, hence the image at a certain zoom looks like a photo without being one. This helps a lot in the subsequent outlining and modeling process.
Apart from whether or not the LE may or may not have this internal camera, this type of work is usually enriched with a complementary photographic study of the entire measured space. The photos taken are finally projected onto the 3D structure, a process that allows obtaining a photo-realistic model. It is something like throwing a sheet spread over a cage: the sheet molds to the shape of its structure, but what we see is the image printed on the cage-shaped sheet, not the structure of the cage. The joint process is somewhat more complex and requires controlling certain positional and metric aspects, but this simplified explanation is enough to understand the general concept: 1) First we obtain the point cloud with the LE; 2) Once in the cabinet and relying on the point cloud, we build the surfaces, the cage or “framework” of the 3D model; and 3) Using the photographic images taken, we “papered” the entire survey, finally obtaining the photo-realistic 3D model of the measured circuit.
LE Static and Mobile. The static method in Iracing videos
Let's now talk a little about the field methodology used with the LE. There are Static and Mobile LEs.
The ones used by the iRacing team in the linked videos are Static. It is already explained in those videos, but basically we must understand that The Static LEs are parked on a tripod and from each of those bases they perform a sweep of everything around them, covering that sweep 360º horizontally and 270º-300º in the upper vertical. Thus, throughout the circuit the LE will be placed in different positions, but remaining static in each of them until completing the sweep from that position. The methodology normally applied (also by the iRacing team) uses a series of spherical targets that are strategically placed throughout the shots, so that from one station to the next consecutive one the LE sees and measures these targets. These function as geometric control and georeferencing points . This, explained in a basic way, is what allows each cloud of points obtained from each base or station of the LE to be ordered later to form the entire block of points of the circuit.
To understand it better, add that when we upload the point clouds obtained from each scan to the computer, each of them is initially in an arbitrary position, disordered with respect to each other, and that these common points, or targets, are used to align all of them until they are arranged in their true spatial position. That alignment is in 3D. This is done in the office, with specific software. There are also different methods here. Some more advanced software does not require the use of targets, but instead analyzes the information and relative position of the points to detect “common shapes” and make the fit, since they have compasses and GPS that allow the shots to not be “so arbitrary”, but rather to keep a certain orientation, not precise, but enough so that the software can make the fine adjustment semi-automatically. But in circuits, since the spaces are so open, it is common to use targets. If the entire process is not carried out with the rigor and positional geometric control necessary in a longitudinal survey of this type, normally several kilometers long and with significant unevenness in many cases, no matter how much relative precision we have with the LE, the topographic survey may not be rigorous, requiring manual fixes or readjustments that will result in work that may be very “impressive”, but not very faithful to reality.
The following iRacing image shows a complete circuit with all the point clouds from each scan already georeferenced. The increased detail serves to explain what those black circles are. They are the different stations where the equipment has been placed. Let us remember that the LE sweeps vertically only 270º-300º, depending on the model, leaving a lower “gap” without taking in generated by the body of the device itself and its support. It can also be seen how around these “gaps” there is greater brillo or apparent luminosity. In reality, what happens is that those nearby areas have a higher density of points, as we already explained. On the other hand, as we move away from the LE, the elements are represented with lower resolution. This is how iRacing has been sweeping the circuits, with static stations strategically placed to cover the entire space to be measured.
To build a 2 km circuit using this method, it is necessary to park the LE at approx. 35 bases, taking about 15-30 million points at each station, making a total of between 600 and 1000 million points, each point with its
iRacing has used in our opinion an excellent working set, in the sense of optimal. Hardware, software, methodology and balanced costs for this type of projects, guaranteeing with this set a very high topographic quality of the point cloud. It has used a “traditional” static method with targets, slower in the field, but which allows guaranteeing constant resolutions and a cloud of points with geometrically very controlled precision.
LE Mobiles
We have read and heard lately that other simulators announce that some of their circuits have also been or are being built with LE systems. The first problem is that when we look for data about these jobs on their websites or outside them, we find almost nothing. They do not explain the procedures, the equipment used, etc. They simply indicate that they have used LE as if that in itself were a guarantee. And here I will talk about the LE Móviles systems, since what we have been able to find accompanying some of those advertisements are photos showing vehicles that have this type of systems. Let's look at some of these photos:
In these two images, you can see a Mobile LE system on the vehicle. On the one hand, we believe that the cameras they carry are video cameras , not photographic cameras, on the other a topographical GPS antenna and finally, on the back, although it is difficult to identify it in these shots, the device LE itself. The appearance of the whole, which only incorporates one LE, the arrangement of the video cameras and the fact that, apparently, it does not have a second GPS to better control the routes, as well as the lack (also apparently) of an odometer, basic in these systems to record the exact distance traveled, make one think that it is a medium-low LE Mobile system cost, faster than static systems, obviously but it cannot reach or guarantee the positional and topographic accuracies of those.
Nürburgring Laser Scan
The same thing happens with the following images. As far as we know, it is the system used to scan the Nürburgring Nordschleife circuit. In them we see a more powerful system, already with two LE on the back and placed in a “V” , but we detect on the other hand that its arrangement is horizontal, that is, the axis of rotation of the LE's optical system is horizontal, parallel to the ground, so the sweeps do not guarantee the capture of vertical elements with precision. This arrangement is no longer used in the most advanced systems, which normally have the same “V” arrangement, but with the two lasers arranged at a certain inclination with respect to the horizontal. The objective of this inclination is that the “slicing” plane that the Laser forms “cuts” diagonally, not vertically, the elements that it finds in its path. If this cut is vertical, it is not possible to guarantee that the representation of the beginnings and ends of the vertical elements or faces are correctly located and defined. On the other hand, also in these images video cameras are again seen and not a photographic system, which is what the most powerful (and expensive) systems carry.
Although this survey of the Nürburgring Nordschleife is a relatively recent project, we believe that it is a non-leading Mobile LE system, and that, like the previous one, it does not reach the guarantees and absolute metric precision of the static system used by iRacing.
We have read in some forum that the iRacing team used one of these Mobile systems to build the circuit of Ímola, but we do not have more data and we do not know if this is the case, what exactly equipment they used and what results they obtained with respect to the static system.
The case of the lifting of the Nürburgring Nordschleife circuit is an atypical case. From what we have been able to find out, here it has not been the simulator company that has carried out the survey, but it has been the circuit itself that has promoted said survey and then offered it to the simulators that want to incorporate it. It is a very smart bet, because this circuit makes an investment that will undoubtedly contribute to increasing its presence in the circuit market and that other drivers or simracers will be interested in getting to know it and visiting it to race on it. We deduce that they have not opted for the static system due to its greater slowness and occupation of the track, especially since this is such a long circuit (21 km) and so topographically complicated. We also miss not having seen the leading brands in Mapping Mobile Systems in an investment of this magnitude, but since we do not have more data, we cannot comment on anything else.
Having said all this, it could be seen that the Mobile LE systems are less guaranteed than the Static ones, but that is not exactly what we are trying to highlight. As we already mentioned when talking about the static systems, the positional control of the LE must be guaranteed precisely along the route, and this aspect is even more delicate and complex to control in mobile systems, which is why if they are not equipped with complementary equipment of maximum quality, its results from a topographical point of view may be questionable, valid perhaps for a simulation game, but not for a simulator whose vocation is to also serve as a professional training system.
There are mixed systems, where the LE operates as a static one, but is transported on a vehicle that makes stops every certain distance. These systems introduce even more uncertainties than the previous ones, but have also been used by some racing games. We will not include images or give more data, because the information in this regard is very dispersed and because it would put more than one person in a commitment, but in many of these sources they speak too lightly of millimeter precision.
Other LE Mobiles
There are also LE Mobile systems that do provide high-performance topographic guarantees. For example, the MX2 system from Trimble, which carries complete equipment: IMU and DMI systems, two GNSS systems and a central photographic system, which together allow the control and synchronization of all records, providing metric and positional guarantees in a mobile system. Trimble is not the only one that carries this equipment, but it is one of the leading brands in this line of products, and its MX2 is a clear example of a LE Mobile system with guarantees. Leica also has a device for this range of services, the Pegasus.
It must be understood that one thing is to carry out the topographical survey of the circuit and another to complete the digital model of it and its integration into a simulator. The rendering of its surfaces, its appearance, the modeling of buildings and vegetation, the light effects, the different adhesions of the track, its physics, the weather, the algorithms that calculate the responses and interactions of the car with the circuit, etc., etc., etc. From that scale, the taking of points with LE only occupies the initial phase of a project that is much more complex, in which many other disciplines intervene, so it is logical to understand that those responsible for these works adapt the methods and systems to be used to their requirements and possibilities, to their human and economic resources. Here the vocation of the simulator is key: it is not the same that it is designed for a console, like a game, or that it aspires to be a professional training system, oriented towards traditional or online competition. But the conditions imposed by the circuits in each case also play an important role, since stopping the normal activity of a circuit like the Nürburgring Nordschleife is something that the circuit may not be able to afford due to the economic losses that this entails.
The acquisition of a LE Static equipment can cost on average around €45,000, while a complete Mobile system is around €250,000, but both can give excellent or mediocre results from a topographical point of view depending on who and how you use them. Obviously, the cost of outsourcing one system or another is also different, and also depends on what you want to obtain.
What I would like to make clear with all this is that a Mobile LE system, with “four cameras on the roof and a GPS antenna” alone does not give the millimeter precision that some advertise, even though the LE itself and occasionally can provide them, since a mobile system requires of other complementary elements that are in turn essential to guarantee that topographic rigor. The managers of these projects should give the simracing community more data, I'm not saying all of it, but more data than what they announce, if they want us to properly value what they offer.
Conclusions
What, in our opinion, is the most substantial and most interesting part of all this? , that it be valued to ensure that the virtual experience is as similar as possible to the real experience, but not only for an aesthetic issue, but also for formal, metric, critical aspect when the simulator managers what they seek is to be, in addition to an online competition platform, a tool for training for professional pilots, since for the latter it is critical that the virtual circuit in which they train certain facets of their preparation is as faithful as possible to the reality they will later face.
The 3D topographic survey of a circuit can be approached today in three ways: 1, by “classical” topographic methods; 2, with static LEs; 3, with LE Móviles. These methods can be complemented in practice, which in fact is what normally happens, but these would be the three independent ways, to understand ourselves, that we could propose if we are looking for a correct topographic survey of a circuit. The first formula, the “classic” , is highly accurate , but the data is discrete (not continuous) and is operationally slower and more laborious. The second method would be with LE, with very good precision and geometric control and excellent cost/effort/time ratio, although it may not be operational if the temporary closure of the circuit is a very critical aspect. The third, LE Mobile. Without a doubt the ideal in this area, due to its speed, even more so if closing the circuit is unfeasible. But be careful!!!, as long as it is carried out with perfectly equipped and adjusted equipment, because otherwise the resulting topography will present errors, jumps and/or gaps in the point cloud, ranges of uncertainty and inadmissible mismatches from a technical topographic point of view. Obviously, all these problems can be hidden and retouched for modeling purposes, but here we come to one of the key points of this article: is it the same for a section of track to have a gradient of 6% as a gradient of 7.5%? Or is it important that a post or a step on a wall is 1 meter before or after where it really is? If the simulator is focused on a game, it may not matter: they are the games that we all know and that put more emphasis on the interior appearance of the car or the shine of the sun on the asphalt, than on the simulation and the competition itself. Be careful, we are not criticizing this at all, we are simply highlighting that it is a different type of approach than the one to which this article aims to address. If, on the other hand, the simulator has another profile and potential audience that it wants to focus on, then it may not be the same. We must understand that the base topography of a circuit is made once, and normally it does not change in essence over a relatively long period. Resurfacing or surface treatments do not normally alter the base topography, not at least substantially.
Obviously, we understand all of the latter in its proper measure. We assume that we are not talking about the construction of the Channel Tunnel, the simulators are not civil works whose errors can endanger the integrity of people. However, iRacing was able to detect this need and look for an appropriate technical solution that would provide that topographical rigor to the point cloud of its circuits. This, in my opinion, makes it very clear what their approach is. Perhaps also for all this, its policy is based on a system of memberships, services, and licenses, with a more long-term focus, and not on the conventional model. And here we come across the price of the circuits that give the title to this article. My interpretation is that iRacing does not see the circuits as a simple inert “game piece”, but as a service that is offered to its clients with the aim of being good, not only in form, but in substance. And that is why they have bothered to disseminate this work, because they want what is behind those 14.95 to be valued.
Without a doubt, iRacing has made a very strong bet, discreet in appearance, but totally professional and rigorous in substance, defined to position itself, also in this aspect, as leader in simulation, also indicating to everyone where to go in the creation of the circuits and contributing to its simracing clients, but also to the professional pilots who use its platform to train, a first-rate applied topographic engineering solution, with a vocation to serve traditional and online training and competition.
We would have loved to talk about the rfactor2 circuits, but we couldn't get information about it. It is without a doubt, if not the best, one of the best simulators of the moment at the physics level, but we insist, we do not have information about how has built the circuits that its platform incorporates. He may not have used LE but he did use other topographical methods. Since we do not have data, we can add nothing more.
Having said all this, we must recognize that the level of detail and quality of the circuits that we are currently enjoyingis spectacular. It is an exciting time in this sense, and virtual reality, fed with these 3D environments, further improves the pilot's experience and the level of immersion. But, precisely for this reason, it also requires better topographical surveys and greater geometric rigor, which is why we expect even better developments, more quality and rigor, and, of course, also more information, to be able to properly value each product.
The question now is, Do you still think that $14.95 is a lot of money? I, honestly, think not, especially when it is a one-time purchase, which is only made once and with it we have true technological gems.
Author's note: I am not part of the consulting for these projects, so, obviously, I do not know what may be behind all of them. I have tried to make a constructive analysis, giving importance above all to the type of approach that I consider to be correct. I have relied on my personal experience as a simracing user, on my technical knowledge and on the data that I have been able to collect and analyze.
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http://www.iracing.com/track-technology/
1) https://youtu.be/mq0MK6aXaV0
2) https://youtu.be/a7GMl4DAWuk
3) https://youtu.be/gVFVdGOmwNQ
https://youtu.be/cUI6HD_d89k?list=PLYInqRsR0uNHZKpDJOrNcIwzwzMCS9RYJ
http://www.trimble.com/Imaging/Trimble-MX2.aspx
http://leica-geosystems.com/products/mobile-sensor-platforms/capture-platforms/leica-pegasus_two
TRIMBLE http://www.trimble.com (Static and Mobile)
FARO http://www.faro.com (static systems only)
LEICA http://www.leica.com (Static and mobile)
TOPCON http://global.topcon.com (Static and Mobile)