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Best approtch to make a low poly marching cubes terrain smoother?

Discussion in 'World Building' started by MCrafterzz, Jun 28, 2019.

  1. MCrafterzz

    MCrafterzz

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    Hey, I'm working on a low poly marching cubes terrain editor and got most stuff working. What I'm really unsure about tho that I haven't found a solution to on google is to smooth it out. As all points have a density value from 0 to 1 it's possible to create smooth terrains like this small example that I did:

    But more often when modifing the terrain it turns out like this:

    Doesn't look so good at all :(. So I want to create a brush that smooths the terrain in a radius to achieve the result in the first picture without manually changing every point again and again, and to make it less tedious. Any ideas? Maybe I can use some sort of blur algoritmen but how?
     
    MCrafterzz, Jun 28, 2019
    #1

  2. jc-drile77

    jc-drile77

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    Hmm I am no expert in this matter so take what I say with a grain of salt.

    I would interpolate each node height value with the ones that are connected to it. That should smooth it out.
    A tool that applies this effect would have a radius and do it for each node within the radius.
    Quick example done in paint:
    (We want to smooth the point (1,5,0))
    upload_2019-6-30_13-11-45.png

    You could even have a factor that gives more weight to the original height.
    For example:

    Factor = 2
    (5*2+3+3.5+3+2.5)/(4+2) = 3,66666667
     
    Last edited: Jun 30, 2019
    jc-drile77, Jun 30, 2019
    #2

  3. MCrafterzz

    MCrafterzz

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    It works quite well to take the average point of the six neightboring points (up/down/left/right/forward/backwards) the only problem is that it seems to always lower the terrain even tho the ground is flat from the beginning.
     
    MCrafterzz, Jun 30, 2019
    #3

  4. jc-drile77

    jc-drile77

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    That is strange. Could you provide the piece of code?
     
    jc-drile77, Jun 30, 2019
    #4

  5. MCrafterzz

    MCrafterzz

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    MCrafterzz, Jun 30, 2019
    #5

  6. jc-drile77

    jc-drile77

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    That´s is a huge chunk of code :rolleyes:
    I would have to study the differents classes and how do they work, but I have little time available.
    Anyways I cannnot see how weighted average (linear interpolation) can reduce the height of a plane parallel to the XZ plane. There must be something wrong somewhere in your code. (n*Z)/n is always Z (disregarding floating-point errors).
    You might also want to try another type of interpolation, perhaps bicubic interpolation.
     
    jc-drile77, Jun 30, 2019
    #6