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HTC Vive lag

Hello,

I’m hoping someone could help me with this. I modeled a house using Autodesk Maya, exported it as FBX. Import into Unreal Engine, on the view port (or work area) it works fine. Get around 60 fps. But when I use virtual reality, things goes a bit downhill. This is what I’m seeing:

  • When looking around, objects appear jittery.
  • The motion controller’s mesh get very jittery.

This spoils the whole experience. I’ve been Googling for answers on this, seems there are some people out there with the same problem. I tried setting latency for controllers, which make it a little slower, but it doesn’t solve the problem.

Here are my specs:
OS: Windows 10 Pro
CPU: Intel Core i7 7800X
Ram: 64GB DDR 4
GPU: GTX 1080 Ti

I can share my project if someone like to see what’s happening. I think it’s performance related. I’m just surprised since I did not make such a complex scene yet. So I believe it has to be solvable somehow. If I need to get a second GPU I would, but I’m hoping there is another way to solve this.

Thanks for anyone willing to help!

did you throw in a lot of dynamic lights?

Viewport fps will always be different from VR. Leaving aside the computation that’s happening behind the motion tracking, the resolution of the Vive will be higher than what you see in-editor. Most likely you still need to optimize the scene. Most likely, judging by your brief description of what you did, you have a fully dynamic scene with no baked lighting. Try building the scene first and play the VR afterwards.

Hello,

Thank you for the replies. Yes I’ve realized the lights (shadows) are contributing the most to the low FPS. I just made the lights movable as it removes the “Preview” from appearing everywhere. So as I understand it, I should have the lights as Static, right? Then it bakes shadows?

Everything else in the scene, for now, is static though.

It’s already running better after making most lights static and baking shadows onto the scene. However I now have another question:

Does a light set to moveable, but shadow casting set to off, cause less performance than if it was set to static? In my mind it’s the shadows that’s causeing lag. So a light that does not cast shadow should not have any problems being set to moveable?

Thanks!

In terms of best to worst:
Static Light with baked shadows >>>>> Movable light without shadows > Stationary light with shadows > Movable light with shadows
(someone correct me if I’m wrong)

Note that Static lights are still dynamic if you don’t press that Build button to bake them

Thanks Link_AJ

That makes sense. It’s hard getting performance up on VR. For me at least. I guess it has something to do with frames being capped at either 90 or 45 and it not being more dynamic.

And yes I’ve realised they stay dynamic if you don’t build first.

Another question concerning lights:

Should I not keep at least the directional light I use for outdoors to moveable? When I set it to static, my trees etc outside looks really bad. The trees has moving leaves and branches, so I’m guessing it would not know what to do with a static light so it just ignores it all together.