Parallax Occlusion Maps On Terrain Textures

Discussion in 'TSW General Discussion' started by TheShotte, Apr 14, 2021.

  1. TheShotte

    TheShotte Well-Known Member

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    So I just asked this on the stream, and was referred to the forums by Matt P. The question is as follows - why don't environment artists use parallax occlusion maps on terrain textures? For example - the ballast on the track does indeed use parallax occlusion maps, and you can tell by looking at it that it has great height to it and looks rather convincing. Now, that same ballast that is often applied to the terrain surrounding the tracks, looks awful and flat because the environment material doesn't have the same maps applied. Why? It's such a simple thing, that would have a great effect on the environments, why do you guys limit the game as such?
     
  2. solicitr

    solicitr Well-Known Member

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    Probably performance.
     
  3. stujoy

    stujoy Well-Known Member

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    It’ll be because it is expensive in performance terms. It’s better to have a flat texture than to have it using up masses of processing power. It’s not even noticeable when driving your train, which is the main activity in TSW. If it wasn’t expensive, they would use it more.
     
  4. TheShotte

    TheShotte Well-Known Member

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    Ok, so a bunch of answers based purely on speculation. Cool. What say you TrainSim-Matt ? Also, I'm not saying to use it on all the environment textures, but at least ballast so that there isn't a visible difference in between the ballast on the terrain as opposed to the tracks.
     
  5. matinakbary

    matinakbary Well-Known Member

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    Well but this is also...

    And Matt doesn't owe you an answer.
     
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  6. DTG Matt

    DTG Matt Executive Producer Staff Member

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    I don't have a complete answer for you yet (kinda busy).

    So far, i've established that it's one of the single worst computationally expensive things you can do with materials, but I haven't yet spoken to people about whether it is something that can be applied in a small area like just around ballast - or whether just having it in the material alone will contribute to growing complexity on it.

    However, i'm talking outside of my expertise and probably badly translating the things those experts tell me, so please wait until I can actually form a coherent answer - I have no idea when that will be currently.

    Matt.
     
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  7. TheShotte

    TheShotte Well-Known Member

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    Even Trainz 2019 has environment textures which include displacement maps, these textures are dubbed with the PBR prefix (procedurally based rendering), although that was a gimmick term used for a layered texture with multiple maps for each that tile seamlessly without horrible patterns.
     
  8. ASRGT

    ASRGT Well-Known Member

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    PBR = Physically based rendering - PBR is not a gimmick if used correctly.

    For example the difference between a PBR and a classic normal texture pipeline would be a normal texture would generally contain 2 -3 maps, they would be a base color map, opacity map and a normal map also known as a bump map, however when it comes to PBR you will often see more than 6 texture maps that container information on Color, Opacity , Metallic , Emissive, Roughness and Normal/high maps but it can go even further with them having maps for Reflection, Gloss, Displacement , Albedo , Fuzz ect. PBR textures are rather involved, this is a gross over simplification of PBR and normal textures however PBR when combined with physical render can produce some stunning results.
     
    Last edited: Apr 18, 2021
  9. TheShotte

    TheShotte Well-Known Member

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    Hey, I only said the actual term was a gimmick, the materials were not at all. It's just what you referred to as PBR, I would refer to as a layered material.

    Also, in terms of performance - when your camera is in any railyard in TSW, you are essentially surrounded by Ballast with displacement/height maps, so you're telling me that the very insignificant amount of ballast on the terrain material would absolutely break performance if it had said height/displacement maps applied? I don't think so. I think this technique was taxing when it was new like a decade or so ago.
     
    Last edited: Apr 21, 2021
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  10. ASRGT

    ASRGT Well-Known Member

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    Understood, sorry if I came across a bit aggressive not my intention :D
     
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  11. mailerdemon

    mailerdemon Member

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    This may be oversimplifying things a bit, but what matters is not how much area is covered by one single material, but rather how many different materials are used. Even in a huge yard, the renderer still has to load the ballast only a single time (assuming that it's a single track loft that is used throughout). So in this case adding a single costly terrain texture would essentially double that load.

    You can observe that effect really well in TS1, when you compare performance after filling a yard in a scenario with thousands of instances of the same piece of equipment or using the same count of vehicles but many different models.

    The comparison to Trainz is also a bit misleading because, as far as I know, it's built strictly for PC and thus can count on the player having more powerful systems in average.
     

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