Fixed framerate or framerate smoothing for VR development?

Hey guys. We’re working in Unreal 4.11 and having a really tough time figuring out the best way to get our animation, ticks, and physics running correctly. What is the standard for Vive development in Unreal between selecting a fixed framerate or framerate smoothing? And if it’s fixed, what is the correct setting? Is it 90? We can’t seem to find the sweet spot. Our physics are very tough to get feeling right and our animations feel ‘floaty’ at times. Any help would be greatly appreciated.

For VR, we are fixed to the framerate that’s provided to us by the HMD APIs. For SteamVR, that’s 90 FPS, which is locked by the compositor. We don’t turn on any sort of framerate smoothing, because it’s fixed at 90 (or 45, if you miss a frame). You shouldn’t need to modify any content for that though, as long as you’re authoring your anims with enough keyframes to adequately interpolate cleanly at 90Hz.

One thing that hits people a lot is if you’re missing framerate, and it drops you to 45 FPS, everything becomes much more jerky because of the decreased framerate and increased jittering in motion making everything look much less smooth. It helps to have the SteamVR perf monitor up while demoing, so if you see a problem, you can verify that you were actually at 90Hz!