3D scanning technology to unlock mountain bike data
3D scanning technology to unlock mountain bike data
Pinkbike is the world's largest mountain bike community and a bellwether for the mountain bike industry. For the benefit of users and readers around the world, it teamed up with Creaform to conduct a suspension analysis. Their blog series 《Behind the Numbers》, written by engineer-turned-driver Dan Roberts, is a category devoted to in-depth analysis of suspensions.
Creaform is very supportive of Dan Roberts' ideas and strives to help him provide rich and accurate shock absorption numbers and data to avid cycling readers. In the metering industry, the speed of the scanner provided by Creaform is particularly outstanding. Not only does Creaform's tool allow for quick setup and quick scanning without surface treatment, but the time required from locating the target point to 3D rendering is very short.
So the team started looking for a Santa Cruz Megatower bike to analyze. Fortunately, Mathieu Performance bike shop in Quebec City (a few kilometers from Creaform headquarters) has a ready-made Megatower to measure.
Get into the actual task: The Creaform team's task was to go to the above bike shop, measure the fulcrum, shaft and tube of the front fork and seat tube, and extract their geometric dimensions. At this point, there is no doubt that the portability of the scanner plays a key role. Therefore, Creaform is the ideal partner for this issue.
1. Quickly set and create a reference frame
The equipment needed for this and any other project is easy to install. The equipment is light and doesn't need to be rigidly fixed. You simply place the bike in front of a piece of cardboard with a target point attached to it.
The positioning target points are paper reflective stickers used to create a reference frame for the 3D scanner's positioning in space. They can be placed on the object being scanned or in its surroundings. To ensure the best tracking, additional target points are needed.
To generate the grid, the scanner should always detect at least three target points in its field of view, but because the geometry and material volume of bicycles are usually loose, a cardboard was placed on the back of the bike to paste more targets.
HandySCAN 3D has a visual field of approximately 30cm X 35cm, which means that the target points should be pasted in a random manner between 2 and 6 inches apart. In this project, due to the complex geometry, different features and various textures of some parts of the entire scanned object, the target points are located relatively close, both on cardboard and on bicycles.
2. Redefine the scanning accuracy of bicycle suspension
Creaform's HandySCAN 3D was used for suspension analysis on short-link bikes, with a local accuracy of 0.025mm. This means that a scan of the bike using HandySCAN 3D can reveal small differences between the design tolerances and specifications (based on the manufacturer's data) and the actual bike. In applications such as quality control during bicycle manufacturing, such a level of precision is not only desirable, but desirable!
3. Grid: compute, build, process
The output data of a surface scan is known as a grid or grid file. The name mesh comes from the virtual look and feel of 3D rendered objects: a woven net, or wire mesh, made up of millions of small triangular surfaces. In this project, we used a triangular size of 0.35mm to capture the feature details we needed to extract, but we simplified the mesh (i.e. creating large triangles on flat areas and retaining small triangles on detailed areas).
HandySCAN 3D can provide a clean mesh surface with triangles as small as 0.1mm. These triangles are used to create bicycle surfaces of varying complexity. Magnified parts are not difficult to find: the number of triangles forming the mesh depends on the level of detail required and the area scanned. You can refer to the image below to see the level of detail captured by the scanner.
One particularly handy feature in Creaform's overall solution is real-time grids. When scanning objects in real life, users can observe the exact data being collected on the VXelements interface. Finally, the data will be converted into a convenient STL file for use by CAD software. That is, the user can immediately see whether a surface or feature is missing throughout the scan.
The amount of data scanned can be quite large, so the system intelligently chooses to simplify the processing to speed up the whole process. In this project, the main elements to be collected are the fulcrum, shaft and tube of the front fork and base tube. Finally, the data collected from the extraction points is used to show the geometry and motion characteristics of the bike.
It sounds like it takes a lot of effort to get a 2D sketch of the bike, but it's so fast and accurate that we can monitor the tolerances of the various parts of the bike.
—— pinkbike.com
4. Output data and export to CAD software
To complete the scanning process, users can use Creaform's proprietary VXmodel software module to import geometric entities (such as fulcrum) directly into the user's preferred CAD software. The module integrates seamlessly with VXelements so that the final 3D scan data can be determined. While CAD software has all the necessary design and modeling capabilities, VXmodel provides the necessary tools for fast and seamless integration into a scann-based design process.
While the scan itself took around 15 minutes, the entire process from setup to the final 3D model took less than an hour.
——pinkbike.com
《Behind the Numbers》series of blogs is popular with readers because it presents real and accurate data. Creaform Remote provided Dan Roberts with a way to accurately measure the short link suspension his team was trying to characterize. Now that Dan Roberts had the numbers all figured out, he did an in-depth kinematic analysis of short-link bikes to determine the actual numbers for lever ratios, anti-sink, anti-rise, axis paths, etc.
