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In VR development, it can only run at a very low frame rate,

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    In VR development, it can only run at a very low frame rate,

    I'm trying to convert a project into a VR project, but I find that there are serious performance problems;

    At present, my project can run at a speed of 200 FPS at 1080p resolution. Even if the resolution is increased to 4K, it can run at a frame rate of more than 100 frames. However, VR requires 90 frames and the resolution is about 3K. From the data point of view, this seems to be enough;

    However, when I actually make it and use non VR operation, I can get 200 FPS (1080p). When I use VR operation, the frame number is only about 45 FPS;

    I have tested many projects, including several official VR demonstration projects and templates of epic, and the results are almost the same. Compared with the performance under 1080p, the performance in VR has lost about six times, which is terrible;

    I even tested different versions of the engine, 4.23 4.24 4.25, all the same results;

    I have set a lot of content in UE4 according to the official settings, but it still fails to meet the expected project. Is the performance of VR so terrible? Need to reach 500 frames at 1080 p to run at 90 frames in VR?



    By the way, I use RTX 2080 Ti graphics card for production. The VR device is HTC vive cosmos. Steam VR and vive cosmos are the latest versions, so it should not be a device problem.



    Is there any solution? This performance is almost impossible, and it's still running on the RTX 2080 Ti

    #2
    Can no one solve the problem? Or is VR really this performance? It's too horrible to do it at all??

    Comment


      #3
      It's too hard why you have such problems with performance, I've created quite a few VR projects but they were VR from scratch. You shouldn't have performance problems, especially with card like RTX 2080 ti. There are special tools for VR that let you monitor performance, but I'm still quite new so haven't used them yet. In case you missed the docs somehow, I'm providing some stuff I found. VR, especially graphics, really makes a performance difference though.

      https://docs.unrealengine.com/en-US/...nce/index.html
      https://docs.unrealengine.com/en-US/...ing/index.html
      https://docs.unrealengine.com/en-US/...iew/index.html
      https://docs.unrealengine.com/en-US/...tup/index.html

      EDIT: On the last link, there's a very important point - "Fake everything you can". Especially shadows, dynamic stuff like this can kill your performance, since it's expensive by default and in VR you're doing it twice (the screen on your monitor is just a projection of your left eye usually, so it's not rendered for the 3rd time as some people think - you can for example change the eye in SteamVR settings).

      Regarding your 45 FPS - as far as I know, this is the magical VR number when you have less than 90 FPS, the framerate is automatically set to 45 to make it stable. It doesn't mean that you have 45 FPS, you probably have more than 45 but less than 90 on your HMD screens, with real 45 FPS only on your desktop monitor.

      https://steamcommunity.com/app/37886...1765131390756/

      It doesn't mean it's OK though. 90 FPS should always be maintained. Some people will feel okay with this, but some not, when it comes to play a final game:
      https://forums.unrealengine.com/deve...feels-ok-to-me
      Last edited by vincent2704; 06-13-2020, 07:09 AM.

      Comment


        #4
        Originally posted by vincent2704 View Post
        It's too hard why you have such problems with performance, I've created quite a few VR projects but they were VR from scratch. You shouldn't have performance problems, especially with card like RTX 2080 ti. There are special tools for VR that let you monitor performance, but I'm still quite new so haven't used them yet. In case you missed the docs somehow, I'm providing some stuff I found. VR, especially graphics, really makes a performance difference though.

        https://docs.unrealengine.com/en-US/...nce/index.html
        https://docs.unrealengine.com/en-US/...ing/index.html
        https://docs.unrealengine.com/en-US/...iew/index.html
        https://docs.unrealengine.com/en-US/...tup/index.html

        EDIT: On the last link, there's a very important point - "Fake everything you can". Especially shadows, dynamic stuff like this can kill your performance, since it's expensive by default and in VR you're doing it twice (the screen on your monitor is just a projection of your left eye usually, so it's not rendered for the 3rd time as some people think - you can for example change the eye in SteamVR settings).

        Regarding your 45 FPS - as far as I know, this is the magical VR number when you have less than 90 FPS, the framerate is automatically set to 45 to make it stable. It doesn't mean that you have 45 FPS, you probably have more than 45 but less than 90 on your HMD screens, with real 45 FPS only on your desktop monitor.

        https://steamcommunity.com/app/37886...1765131390756/

        It doesn't mean it's OK though. 90 FPS should always be maintained. Some people will feel okay with this, but some not, when it comes to play a final game:
        https://forums.unrealengine.com/deve...feels-ok-to-me
        Hello, thank you for your answer. I will do further performance analysis on VR and try to find out the problem;

        Now I am confused that my project can run 200-300 FPS under 1080p in non VR. Even if it is upgraded to 4K resolution, it can maintain 100 + frame rate;

        According to the data, the HTC vive cosmos device I use has a resolution of only 2800 * 1700, less than 3K. If I extrapolate from the data, the performance here should be stable 150 +.

        But the actual situation is as bad as I described above. Most of the time, it's only 45. Even if it's caused by the vertical synchronization within VR, it still means that 90 FPS can't be stabilized most of the time?

        It seems that the resolution of this data and device is not quite right. Do you have the same performance in your VR development?

        Comment


          #5
          VR doesn´t work like that. Its not a matter of framerate only. I would recommend you to check documentation on how to setup and optimize a VR project.
          Check out Vincent´s´s links and also is helpful
          https://developer.oculus.com/documen...ced-rendering/

          Hope it helps,
          https://vimeo.com/395997583

          Comment


            #6
            Originally posted by malcriado View Post
            VR doesn´t work like that. Its not a matter of framerate only. I would recommend you to check documentation on how to setup and optimize a VR project.
            Check out Vincent´s´s links and also is helpful
            https://developer.oculus.com/documen...ced-rendering/

            Hope it helps,
            Hello, I am using HTC vive cosmos device for development. What I am confused about is the resolution data based on VR, which should not consume so much performance. The current situation is that the consumption of 3K resolution in VR is almost equal to the consumption of 4k-5k level in non VR, and I am using static light + forward rendering. Is there any problem with this data? Or VR itself has such a high consumption?

            As mentioned above, my scene 1080p can run with 200 + FPS, even 300 +, and can run stably with 120 + at 4K resolution. However, in VR, the latency I see through the streamvr performance view is about 12 milliseconds, that is to say, less than 90 FPs in reality, and most of the time will be forcibly reduced to 45 FPS, which is obviously different from the data;

            Comment

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