Fourteen dollars and ninety-five cents is the current price of a track in iRacing. Is it a high or reasonable price? I’d say that, like everything, it depends on how you look at it. What’s beyond doubt is that tracks are where we’ll spend the most in this simulator, because while you can focus on a few car classes and stick with them for a while, the list of tracks in a series varies, so running a season with some consistency requires owning a good number of them—especially if you race both oval and road. However, the goal of this article isn’t to discuss the cost of racing in iRacing; instead, we’ll focus on 3D Laser Scanning systems to understand what they are and how they’re used to create the simulation tracks we race on.
The Use of Laser Scanners in Track Surveying
Simracing and motorsport enthusiasts already know—or have at least heard—that the tracks in next-generation simulators are created using Laser Scanner technology (hereinafter referred to as LS). In reality, they aren’t exactly “created with” it, but rather built from the points obtained by this type of equipment. In other words, LS is used to perform the 3D topographic survey of the track.
Surveying and cartography engineers have been measuring tracks for decades, though they previously used other topographic tools. The need for precise technical track plans isn’t new—it has long been a requirement for professional racing teams to study layouts in detail and improve lap times.
Before Laser Scanners…
Before today’s 3D simulation systems, paper track plans and/or 2D computer systems were used to analyze racing lines. In fact, systems similar to raceoptimal are still in use today for these kinds of studies, though modern systems are obviously far more advanced. However, none of this holds value without an accurate geometric representation of the track.
LS systems are simply an evolution in measurement techniques. Previously, surveying engineers used theodolites and levels, then total stations, followed by topographic GPS equipment, and now the trend is toward LS. Traditional methods were highly invasive and required partial or total shutdowns of track activity, as the surveying team needed to be present for days or weeks, depending on the track and project requirements. Surveying an entire 3 km track could take several weeks of full-time work. But that’s what was available, and professional racing teams fed their studies and simulation systems with topographic surveys of this kind, as reliable data was (and is) critical for them.
These topographic surveys, though extremely precise down to the millimeter, were still a discrete model of reality, meaning not continuous. The surveying engineer decided which points to measure to capture the track’s elements. When using such equipment to measure, say, a wall or the track’s edge line, you’d select the points needed to define its geometry—but no more. You wouldn’t measure a point every centimeter or a thousand points to trace an arc; you’d discretize, because it wasn’t strictly necessary and otherwise you’d never finish, not even in ten years.
Advantages of Laser Scanner Systems
And this is precisely the main reason LS systems have become dominant: they drastically reduce scanning time, on one hand, and provide near-continuous surveys, on the other. Additionally, while elements and spaces around the track—runoff areas, fences, walls, etc.—were previously “invented” and modeled based on cartographic data or environmental photos, LS now measures them too, capturing all the key data for a complete track survey in a single sweep, not just the track itself. This is significant because these peripheral elements often serve as visual reference points for drivers. The more accurately these are positioned, the more complete and true-to-life the experience becomes.
That said, if we’re told a track was surveyed with LS, we shouldn’t automatically assume the absolute topographic precision is exceptionally high or better than traditional methods. We’ll have more points, yes, but not necessarily better ones. Some simulators market their LS work as a selling point, and we’ll see that, in part and in some cases, these are highly sensationalized claims—not because LS devices lack top-tier performance (they don’t), but because the results of an LS topographic survey, the positional accuracy of the points obtained, depend on various factors: distance, methodology, and the complementary systems used alongside the LS, not just the LS itself. Ultimately, as with everything, results depend on the technology we use, but above all, on how we apply it. We’ll delve into this further later.
Origin and Applications of Lasers
The word “laser” is an acronym for 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’ve been developed and refined, serving numerous sciences and professional fields. One such field, as we’ve seen, is measurement in Topographic Engineering.
In Spain, the two university degrees specialized in using LS as measurement tools are the Technical Engineer in Geomatics and Topography (http://www.coit-topografia.es/) and its higher-level counterpart, the Senior Engineer in Topography, Geodesy, and Cartography (http://www.topografia.upm.es/portal/site/ETSITopografia). Of course, they aren’t the only professionals who use this equipment, but they are undoubtedly the most qualified by their academic training to do so correctly, mastering the methodology, ensuring the required precision for each project, and combining these techniques with complementary measurement and positioning systems to adjust and georeference the collected data.
Topographic Methodology in iRacing
In the videos iRacing has posted on its website to explain how they’ve used this technology to survey tracks, you’ll see typical topographic equipment. The methodology applied is pure topography: polygonal traverses and linking techniques that maintain the necessary geometric control and overlap to a) cover the entire track with successive stations and b) georeference all the scans taken. The LS seen in those iRacing videos is from Leica, a multinational manufacturer of topographic equipment through its Leica Geosystem group. Trimble also offers such devices, like its Trimble TX8 Scanner, and FARO is another noteworthy brand. There are other companies, but these three are perhaps the most prominent in this field.
How a Laser Scanner Works
But how does an LS operate? The LS’s internal hardware essentially emits a laser beam and measures the time it takes to return to the device. It includes optoelectronic systems for emitting and receiving the beam, controlling the device’s angular positions, and processing the recorded data (I’ll link some explanatory videos at the end). Since the device knows the beam’s characteristics with great precision—its speed through the air, the time it takes, and even environmental conditions thanks to internal sensors—it calculates the distance to the object or obstacle that caused the beam to bounce back.
Combined with the fact that the device constantly tracks the relative geometry of the emitted beams—the vertical and horizontal angles of each signal sent and received—the system can assign XYZ coordinates to the recorded data, which are, ultimately, points in 3D space around the LS.
In reality, the LS doesn’t emit a single pulse but hundreds of thousands per second—enough to achieve the required resolutions and averages. You can imagine this is far more complex than it sounds: there are time-measurement scanners and triangulation scanners, depending on how they measure distances, and the former are further divided into time-of-flight or phase-comparison lasers, each with its pros and cons, suited to different goals and requirements. These are different developments within the same technology we broadly call LS. We won’t dive into all this, of course, as it’s “a whole different ballgame.”
It’s worth noting, however, that not all LS devices operate with the same resolutions and quality levels or have the same distance ranges. In fact, a single LS unit can offer different resolution and quality settings, as some cases demand very fine results while others don’t. Resolution and Quality are the two most critical parameters in an LS: Resolution is the distance between points, which depends on how far objects are from the LS’s position—meaning, for the same scan resolution, objects closer to the LS will be represented by a denser point cloud. Quality is how many times the LS measures each point, as it takes multiple measurements—not just one—to average and determine the most likely distance for each point. LS devices can also be classified by range: short-range for measuring caves, facilities, or indoor buildings (up to 30-40 m), medium-range (up to 120 m), and long-range (typically around 350 m). There are even longer-range ones for aerial surveys, but we won’t cover those.
Capabilities of Modern Laser Scanners
Most cutting-edge LS devices can capture up to 1,000,000 points per second. Yes, you read that right—one million points per second. And that’s not all: they achieve XYZ coordinates for each point with precision under 1 cm. Beyond XYZ coordinates, the LS records the surface’s reflectance and assigns each point its corresponding value, allowing interpretation of the scanned surfaces and textures. The resulting point cloud, though unstructured, is so dense that it forms an image that clearly conveys the shape and texture of the scanned objects. Additionally, some LS units have an internal camera that assigns each point an RGB color, greatly enhancing point cloud analysis by making it look like a photograph of the scanned space at certain zoom levels.
After scanning a track with an LS, what we get is simply a point cloud used to identify the measured elements in the office. Based on this data—which isn’t yet a surface or a proper structural element, just points in space—we begin working to create a final 3D model.
From Scanning to a Photorealistic 3D Model
Beyond whether the LS includes an internal camera, these projects are often enriched with a complementary photographic study of the entire scanned space. The photos taken are ultimately projected onto the 3D structure, a process that yields a photorealistic model. It’s a bit like throwing a stretched sheet over a cage: the sheet molds to the structure’s shape, but what we see is the image printed on the sheet in the form of a cage, not the cage’s framework itself. The combined process is more complex and requires controlling certain positional and metric aspects, but this simplified explanation captures the general idea: 1) First, we obtain the point cloud with the LS; 2) In the office, using the point cloud, we build the surfaces—the “cage” or framework of the 3D model; and 3) Using the photographs taken, we “wallpaper” the entire survey, resulting in a photorealistic 3D model of the scanned track.