[SOLVED] Weird "bumps" in the terrain when placing rails

  • Hello,


    I'm at the step of adding tracks to my semi-real map (with DEM-data), but why is it, that the terrain generates random bumps here and there between the rails whenever I'm adding them? Shouldn't the terrain readjust evenly to the track height? It does this even with subgrades in place beforehand.

  • Hmm... well, it did, sort of. But not all of the bumps went away.


    Until now, I've placed the track with a relative height of -0.15. I just tried placing them at 0, and at the very moment, it looks ok:

    Exact same location.


    However, there is still another issue: When I try to connect two segments together, it simply won't let me. Instead, it just creates this weird circular track:


    The top panel:


    It only works if I place down to perfectly straight tracks, as I did to test.

    Why is this? What am I doing wrong here?

  • If you place the tracks on -0.15 m, the terrain thinks it has to get between the tracks on 0.00 m. This is the "problem" here. This means, if you are building the road/ grass/... on -0.15 m the terrain nows, that it doesn t have to go up to 0.00m. When you later build the landscape, this "problem" should be solved.


    For your second issue, the tracks are not perfectly oriented in this case. If you try to connect with a new track from the top side, it will show a long curve which will not fit with the end (on the bottom). The solution is to adjust one end (bottom or top track) to the other track, then you can add a new track and it should fit.


    Adjust means to click on one large triangle and then to click on the other large triangle, when you can "move" the end of the track. (I hope it is understandable ^^)

  • It makes sense to me. :)


    It's because, in Florian's tutorial he mentions that the rail head should be, together with the street, at -0.15. But in the end I could just place the curbstones and such at +0.15, I guess?


    Aaaand I JUST discovered, that the weird terrain gen with the bumps is somehow related to the length of the rail spline. If it >100 meters, it fails, but at <100 meters, it is still fine (at least, that's my theory).


    Thank you for the tip, can confirm it works. ;)


    -Thor

  • I think the realisation with the street on -0.15 shall help to not lift up the (whole) landscape/ environment to +0.15. That s correct:

    Street at -0.15 -> landscape 0.00

    Street at 0.00 -> landscape +0.15 (in urban areas - outside of urban areas the height is not that relevant)


    It is necessary to use terrain elements to have a "basic frame" for the streets, tracks, etc., when you are building a map with DEM. Otherwise you maybe get problems with slopes, terrain gen and other stuff.


    Important for splines, tracks, etc.:

    They should not be too long. I ve heard from the tutorials, that 25m could be a good length. 50m or a bit more should not be a problem, but keep that in mind.

  • Well, apparently it was ok, but it later turned out to be just as bad.


    I'm this close to giving up completely; no matter what order or height I place the subgrades and rails at, the terrain still gets bumpy everywhere:


    Rail properties:


    Subgrade properties (raised to 8m for testing; the "real" height from Google Earth is ~4m):


    Isn't the idea of the subgrade to smooth out the terrain inside it? Does it have something to do with the DEM?

    Someone please explain it to me and what I should do, I really don't want to give up building my map because of the terrain acting weird. :<

  • One important fact is perhaps, that (in contrast to the splines, polygons etc.) the railtracks have an absolute height in any case! So even if you don't mind the height of polygons or splines, you have to pay attention to or have to correct the height of your tracks!


    Perhaps you should take a look into this article: https://www.lotus-simulator.de…ain-subgrades-railtracks/

  • Marcel Kuhnt ,

    Thank you for the answer, but I already knew about the difference of absolute and relative height. And as I understand it, if I initially lay down tracks relative to the terrain, they'll stay at that exact location due to their absolute height.


    I created another little "test" (rails first, then subgrade):


    The terrain follows the subgrade at the sides as I expected it to do. But, and this is really my main confusion: Shouldn't the terrain between the rails be perfectly flat, parallel to the rails due to the absolute height of these? Why is it then creating such a spike?? And the terrain just next to the terrain is jagged as well, when it's nearly smooth at the curved sides of the subgrade?

  • But, and this is really my main confusion: Shouldn't the terrain between the rails be perfectly flat, parallel to the rails due to the absolute height of these? Why is it then creating such a spike??

    No, the terrain has its height also between the rails. As usual you place spline or polygons over the rail area which flattens the terrain to the correct height. You can check the terrain in the environment tab on the left. There you have got the wireframe checkbox, which you can activate to see the terrain in wireframe mode. So if there is a vertex of terrain between the rails, the terrain has bumps between two rails. Otherwise the terrain is flat.


    Greets

  • As usual you place spline or polygons over the rail area which flattens the terrain to the correct height.

    Yes, but no.


    I have this traffic island from a while back:


    Which is flat. Now if I add a polygon:



    It makes it WORSE??? The exact opposite of what you wrote?

  • The polygone height of the street is, for example, "0" .The Island, height of the polygon must be set to "0.15"

  • It makes it WORSE??? The exact opposite of what you wrote?

    If there is no polygone, the wireframe ist much more rough than if you place a polygone. So even if the polygone has the same height, it could be more bumpy because there are more edges between your curbstones...

  • Even with the polygon set to 0.15 height, it still generates bumps. I'm sorry to say... :(

    Right click on the polygon, Properties..., Untick Vertical adaption at curting

  • It worked now, thanks to me being an initial dumbass :P


    It was only the initial polygon point, which was 0.15... When attaching it to all the other attachpoints (which were at 0, placed when I didn't know), every other point than the first placed in the new polygon became 0.00 as well...


    I hope my issues will keep to a minimal for now... Thank you all for the help :D

  • thor2950

    Changed the title of the thread from “Weird "bumps" in the terrain when placing rails” to “[SOLVED] Weird "bumps" in the terrain when placing rails”.