What does digitally scanned tracks actually mean.

Discussion in 'General Discussion' started by Steve Cunningham, Oct 29, 2022.

  1. Steve Cunningham

    Steve Cunningham Registered

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    Is a digitally scanned track somehow easier to implement into the game then creating the track and details ?

    Just curious what it takes to digitally scan something and make a track ? I imagine it is not a plug and play thing that can just be scanned by driving around the neighborhood and making a track in your area from that.

    Please describe this subject and also how a scanned track is put into the game and what is required to do so. Is it extensive manhours of programming involved or is there some sort of scanning modeling app that makes it easier somehow ?

    Just curious how it all works and why scanning tracks is better then making them. Thanks
     
  2. davehenrie

    davehenrie Registered

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    Often laser scanned tracks are more expensive due to having to pay for the scanning process before any work can be done to incorporate it into a sim. The short answer is DETAILS, laser scanning reveals more small bumps, more uneven surfaces, it gets the track width exactly right, the length of the circuit exactly right, you get elevation changes spot on rather than approximated by the track builder. Usually there is so much detail that it has to be scaled down to run in a reasonable speed with today's computers. Prior to laser scanning, tracks were hand drawn by crafters looking at video or pictures. You still can do an amazing job with that method but rarely do the non-scanned tracks work out as precise as lasers.(notice I did not say ALWAYS)
    Now, as to HOW it's implemented???? Somebody else will have to fill that part in. But here is a link to the original release announcement of the first Laser scanned track by S397 for rF2. It has some screen grabs of what a computer tracks is really all about.
    https://www.studio-397.com/2018/07/sebring/
    and here is a great read about how a track is hand-crafted.
    https://forum.studio-397.com/index....ay-from-scratch-2022-wec-style-for-gem.72483/
     
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  3. Coutie

    Coutie Moderator Staff Member

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    Yes, it's easier, since you don't have to guess the elevation, you just create the driving surface on top of the laser scan.
    No you can't just scan and put into the game, the point cloud has hundreds of millions of vertices, which is not usable in-game. Methods of creating the roads could vary, as they say, there's many ways to skin a cat.
    Here's a link that shows how to create a mesh from a point cloud: https://assettocorsamods.net/threads/lidar-point-cloud-to-mesh-tutorial.422/
     
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  4. Emery

    Emery Registered

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    Digitally scanned is a broad term that also includes photogrammetry, photo matching, and color returns for lidar. These techniques help guide shape and in-game color of terrain and objects.

     
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  5. Steve Cunningham

    Steve Cunningham Registered

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    WOW
    So it's not something most people want to tackle unless they have some programming and modeling backround. Likely experienced and not a beginner. So this answers that. Thanks
     
  6. Steve Cunningham

    Steve Cunningham Registered

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    So what type of scanning devices are required to even get a scanned track that someone would work with.
     
  7. Emery

    Emery Registered

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    Contract services for mobile (car/van) or survey lidar are usually hired to generate the most detailed point clouds. The point clouds are stupidly dense and accurate. Multiple scans are stitched together, so the contractor needs to compensate/calibrate as they go or else the scans won't mate well and that's where they earn their keep.

    Aerial lidar is usually available via government web sites (I know USA, UK, Australia, Holland, France, & Italy have data available). The point clouds are usually 0.5-1 meter resolution horizontal, with centimeter accuracy.

    And finally, the newer cellphones have lidar capability built-in, but need software to make good scans, as shown in the video I posted above.

    Hopefully the points have been classified by signal strength and timing characteristics as ground returns or vegetation returns, but, if not, then there is free software (LASTools) to do that work. Cloud Compare is the free tool for editing point clouds and turning them into polygons for 3D editing software (e.g. Blender) to finish.

    What's not talked about much is how vegetation affects lidar. When you're looking at a point cloud, you generally strip off the vegetation point returns & telephone wires and only use the ground point returns to build the track terrain & buildings. In a dense forest, aerial lidar is not going to give you very many ground returns, so it's necessary to interpolate and/or match photos. Then you might look at the tall vegetation returns to give the trees the right height. The fuzzy vegetation point returns can be used to size the grass & low shrubs, but generally not so often.
     
  8. Alex Sawczuk

    Alex Sawczuk Administrator Staff Member

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    It's not realistic to create real time meshes directly from point clouds. You overlay hand made ones onto them.
     
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  9. Diogo Silva2

    Diogo Silva2 Registered

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    Once upon a time in quarantine i tried to work a track. I got the point clouds, then created flat meshes, and with 3dsMax object paint i was able to align meshes on point clouds. I get a really good racesurface, suprisingly.

    Not sure if there is other tool or other proper way to do it.
     
  10. Coutie

    Coutie Moderator Staff Member

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    Ya, that's how it's done. There are scripts for max that are way faster than object paint though(as in performance).
     
  11. Comante

    Comante Registered

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    It's a job that require high technology and art. but the opportunity to feed into the simulation a realistic (and real) road mesh is uncomparable. Just like in R/L you learn to know each bump or slope in the street you ride daily, the same happen on the simulated track
     

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