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separate geometry or seamless meshes? and building question

lockey1995
lockey1995
polycounter lvl 5
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lockey1995 polycounter lvl 5
Hey Poly counters been a long time lurker on here now and never got around to making an account but finally i have and I'm looking to improve so may post more in future :). So the first thing I was interested in learning is what's in the title so at the moment I can't remember where I heard it but it basically said if it's separate in the real life counter part it's generally separate in the model as well so I've stuck to this since but is there any drawbacks to this really or is it just preference? 

So I'm guessing a door,window/window frame you would do as a separate mesh instead of adding cuts everywhere, cutting, offsetting and extruding in wards I ask this because I'm currently making a building for a racing game and I have done the windows and doors as a separate mesh and just wondered if it was really the correct approach to it. 

Basically I'm just confused on when you would probably opt for a seamless mesh over doing it in separate pieces so it would be good to hear more experienced people's opinions to see if I'm on the correct path or not. One thing that did give me a head ache was in the image below the window cut outs are extruded in wards towards the building and this mounted up pretty fast with the amount of windows I had to do so there was allot of clean up involved and wasn't happy with it at all but I don't think there's really a way around this is there really as it needs to be done on the building it self was just looking for cleaner alternatives if there was any in future. 

Took a photo to what i was referring to in the above:  https://prnt.sc/lzj24x


Cheers :)





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  • poly_troubleshoot
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    poly_troubleshoot polycounter lvl 3
    You don't want to make the whole thing as one continuous mesh. If you want to make a building or a constructed environment, learn about modularity.

    http://wiki.polycount.com/wiki/Modular_environments

    https://www.youtube.com/watch?v=MfA5bhhS1m0
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  • lockey1995
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    lockey1995 polycounter lvl 5
    Thank you will take a look :)
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  • lockey1995
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    lockey1995 polycounter lvl 5
    poly_troubleshoot said:
    You don't want to make the whole thing as one continuous mesh. If you want to make a building or a constructed environment, learn about modularity.

    http://wiki.polycount.com/wiki/Modular_environments

    https://www.youtube.com/watch?v=MfA5bhhS1m0
    Never thought about doing modular for a building for a simtrack but definitely might try it :)
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  • RyanB
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    RyanB
    Every unique mesh = 1 draw call
    There is a limit to the number of draw calls your GPU can handle.  Every game and every hardware platform has unique limits.
    If your building uses 8 unique meshes, that will be at least 8 draw calls.

    In your case, you are making a building for a racing game.  I assume you aren't entering the building or getting too close.
    Why make the door a separate mesh in this case?  Will the door open?  Probably not.  So, making it a separate mesh is just another draw call that could be saved if it was part of the mesh.  Same for the windows.

    If you were making an FPS, then making the door separate makes sense.

    Another option is to combine your meshes using a script before run-time. 

    Ultimately, you will need to profile the game and optimize from that information.




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  • suspectlogic
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    suspectlogic polycounter lvl 13
    RyanB said:
    Every unique mesh = 1 draw call
    There is a limit to the number of draw calls your GPU can handle.  Every game and every hardware platform has unique limits.
    If your building uses 8 unique meshes, that will be at least 8 draw calls.

    The last part is only true in specific situations. If the meshes use the same materials  and are static then they can be static batched to reduce draw calls (in Unity anyway)

    @lockey1995

    Some other  questions you can ask yourself:

    - what is the required level of detail?

    - will you you need to bake lightmaps? if yes, will the lightmap resolution benefit from separate or seamless geo? 

    Edit: I agree with what RyanB mentioned, profiling will help answer most of your questions.
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  • lockey1995
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    lockey1995 polycounter lvl 5
    Thank you :)
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  • lockey1995
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    lockey1995 polycounter lvl 5
    RyanB said:
    Every unique mesh = 1 draw call
    There is a limit to the number of draw calls your GPU can handle.  Every game and every hardware platform has unique limits.
    If your building uses 8 unique meshes, that will be at least 8 draw calls.

    In your case, you are making a building for a racing game.  I assume you aren't entering the building or getting too close.
    Why make the door a separate mesh in this case?  Will the door open?  Probably not.  So, making it a separate mesh is just another draw call that could be saved if it was part of the mesh.  Same for the windows.

    If you were making an FPS, then making the door separate makes sense.

    Another option is to combine your meshes using a script before run-time. 

    Ultimately, you will need to profile the game and optimize from that information.




    I think i did it that way because I hated edge loops being everywhere and having to clean a ton of stuff up later on 
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  • jStins
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    jStins interpolator
    Don't confuse 'combined meshes' for 'modeled as one piece'. You can model doors, windows, walls, etc separately (easier this way for sure), then combine them in your modeling package (mesh -> combine in Maya for example) or in your game engine as RyanB mentioned. Meshes can be combined without their geometry being 'physically' attached.


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  • lockey1995
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    lockey1995 polycounter lvl 5
    jStins said:
    Don't confuse 'combined meshes' for 'modeled as one piece'. You can model doors, windows, walls, etc separately (easier this way for sure), then combine them in your modeling package (mesh -> combine in Maya for example) or in your game engine as RyanB mentioned. Meshes can be combined without their geometry being 'physically' attached.


    Yeah they're all combined at the end yes 
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  • lockey1995
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    lockey1995 polycounter lvl 5
    lockey1995 said:
    poly_troubleshoot said:
    You don't want to make the whole thing as one continuous mesh. If you want to make a building or a constructed environment, learn about modularity.

    http://wiki.polycount.com/wiki/Modular_environments

    https://www.youtube.com/watch?v=MfA5bhhS1m0
    Never thought about doing modular for a building for a simtrack but definitely might try it :)

    I just tried this out and wow it's really good I'll be using it from now on created the main pit building in the photo in about 15-20 mins when I had all of my pieces set out
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