How do you make out of bound areas?

Discussion in 'Mapping Questions & Discussion' started by The Whole Team, Jan 23, 2010.

  1. The Whole Team

    The Whole Team L1: Registered

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    I'm not talking about the spots RIGHT out of the spawn. I'm talking more about how the horizon is WAY out there on a lot of the maps. Like in granery, far off you can see barns, an ocean and a ship. I looked in the decompiled granery map and there's some sort of sealed off area containing the background, but I don't really get it.

    Could anybody tell me how that works or just link a guide? Thanks in advance.
     
  2. VelvetFistIronGlove

    aa VelvetFistIronGlove

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  3. Terr

    aa Terr Cranky Coder

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    To toss a metaphor on there... the walls are painted with special holographic digital paint.

    This technopaint relays the scene from a special camera located in an isolated room where tiny dollhouse versions of whatever you want to show is.
     
  4. Engineer

    aa Engineer

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    This tutorial as well as the valve one should explain everything. ;)
     
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  5. Trotim

    aa Trotim

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    That very far away stuff is the 3D Skybox; the "out of bounds" area is usually more the area right behind the fences that is not part of the playable map area but still no skybox yet.
     
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  6. Pocket

    aa Pocket func_croc

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    Oh, and just in case you were wondering, the skybox really can be made to line up seamlessly with the map proper, even though Valve have apparently chosen not to design their maps that way (there's always a drop-off and texture shift of some kind).
     
  7. VelvetFistIronGlove

    aa VelvetFistIronGlove

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    I can think of two good reasons:

    First, if there's a clear visual difference, it helps to lampshade that it's an unplayable area of the map.

    Second, you want the 3D skybox to be low detail, since it is always rendered; so by not making it seamless you get a clear boundary (e.g. a fence) between the highly detailed areas of the map and the low-detail 3D skybox.
     
  8. grazr

    aa grazr Old Man Mutant Ninja Turtle

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    I disagree, there's no reason why the 3dskybox should be less detailed when it's already rendered at 1/16th of the original. That in itself is saving us system resources. Players are already aware of the map boundaries by fences and walls; this is not what the skybox represents. The 3dskybox is never right up against a fence otherwise it would be too noticable by players. There's usually a 1024-2048 lip of real world details before the skybox comes into view; and even then cliffs or huge buildings usually obstruct the horizon.

    Obviously you don't want the skybox to be crazily detailed, but some of the skyboxes at the moment are crap. 2fort's is about as good as it gets right now.
     
  9. VelvetFistIronGlove

    aa VelvetFistIronGlove

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    No, the 1/16th scale of the skybox does nothing to "save system resources", except that the default lightmap resolution will be 16x smaller. Since the 3D skybox is considered always visible, it is in general more expensive to have details in the 3D skybox than in the map proper, since details in the map can be skipped from all rendering calculations if they are in visleafs that are not being shown.

    Details do not belong in the 3D skybox; instead, put them in playerclipped detail areas of the map that connect (seamlessly if you want) to the 3D skybox.
     
  10. Remix

    Remix L69: Deviant Member

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    Agreed. If you find yourself looking out into the skybox on a properly made map with a good layout and flow, then you aren't helping your team or completing the objective.

    Make the areas that people will use the most look the best. Valve's use of the 3d skybox system in TF2 seems very effective to me.
     
  11. Mr.Late

    Mr.Late L7: Fancy Member

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    Remember that the textures and models in 3D skybox are also 16x smaller. (In hammer)
    E: Also 3D skybox is not always rendered. (If I understood right)
    Compare this to this
     
    Last edited: Jan 26, 2010
  12. VelvetFistIronGlove

    aa VelvetFistIronGlove

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    OK, A small clarification: the 3D skybox is not always fully drawn to the display buffer: when the game comes to render it, the only pixels of the 3D skybox (and 2D skybox behind it) that are actually drawn are those where the z-buffer is empty, i.e. where something in the world has not already been drawn. But that is the final stage of rendering; all the polygons, textures, entities in the 3D skybox will have been included in all the lighting and transform calculations up to that point. (It is also possible that the game will not render the 3D skybox if none of the visleaves in the PVS use the toolsskybox texture, but I don't know whether such an optimisation is used.)

    What's happening in your two pictures, Misteri, is this: The game draws the world, with both z-buffering and z-culling so that things further away correctly get obscured by things closer to hand. It then draws the world's wireframe, without z-culling, so that the wireframe is visible above all the world objects. It then draws the skybox with z-culling, at a z of 'infinity' (so it never appears in front of any of the world); and finally draws the skybox wireframe, still with z-culling. The 3d skybox is still included in rendering calculations, but it and its wireframe will always appear to be covered up by any world objects..
     
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  13. Mr.Late

    Mr.Late L7: Fancy Member

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    Ah, ok :p
     
  14. Remix

    Remix L69: Deviant Member

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    Very useful stuff to know for larger maps. Thanks for that bit VFIG.
     
  15. grazr

    aa grazr Old Man Mutant Ninja Turtle

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    In that case someone needs to rewrite the 3Dskybox entry over at the Developer Wiki.

     
    Last edited: Jan 27, 2010
  16. Firest0rm

    Firest0rm L4: Comfortable Member

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    another argument for not detailing the 3d skybox as much as you would a regular area: you want it to appear unplayable. If your 3d skybox looks like it would be fun to play in, players will want to do so. They will be frustrated by their inability to play in the interesting looking area.

    For example, take the really low fence in hydro. If the area behind it looked pretty and meant for playing in, players would get frutstrated at their inability to go over what should be a low fence, not a wall, and might dislike the map because of that
     
  17. grazr

    aa grazr Old Man Mutant Ninja Turtle

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    Things really don't work that way ingame. Players are focused on killing enemies and achieving objectives; not trying to play in detail areas.

    Just look at Goldrush and 2fort for a number of examples. Instead of trying to jump the 4ft high fence parallel to the raised mining tracks, the 16 attackers are pushing the payload to the first capture point, and the 16 defenders are killing the 16 attackers. Demomen and soldiers arn't trying to jump out of the map to play in the gully beyond the 8ft fence, but jumping onto the enemy battlements to kill those pesky snipers, and eventually capture the intel. These curiosities are only prioritized in moments where players arn't in danger. Such as in spawn looking into a detail room; where they can afford to briefly pass their attention to the surrounding details, as opposed to their (more significant) enemies.

    But as i said, you don't want it to be crazily detailed, as much as you wouldn't want the 'map proper' crazily detailed. It goes without saying that the more detail comes the need to use more system resources to render said detail. The sort of visual mechanics you are implying, however, occur under different gameplay rules. Such as single player, where the above mechanics are not apparent.
     
    Last edited: Jan 27, 2010
  18. chickenm4n

    chickenm4n L1: Registered

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    well what you highlighted might be different.

    velvetironfistglove said that it doesn't save system resources while in game.

    the wiki just says that it compiles faster and helps with the EDITOR views.

    when it's in game is where system resources aren't saved (i.e. when the minature skybox is rendered at 16 times bigger)
     
  19. VelvetFistIronGlove

    aa VelvetFistIronGlove

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    I think that sentence in the wiki is referring to what comes after it:
    [q]Due to their scale, 3D skyboxes have much lower lightmap and texture resolution. This makes 3D skybox geometry less expensive performance-wise than standard world geometry.[/q]
    They will have much lower lightmap resolution, and will usually also have lower texture resolution; this will improve compile speeds (as will not having to do vis calculations for the skybox), and will save video memory, but don't enormously improve the rendering speed.
     
  20. martijntje

    martijntje L8: Fancy Shmancy Member

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    to make the world look bigger, if you look at a random skybox you will see that the "playable world" is a lot smaller than the "full world"