# Fix ## Motion BLur in viewport : To optimise on-disk storage, when we export USD files we cull time samples that are "out-of-range". For example, if you're only rendering frame 10, then you only need the samples from frame 10 ... ish. Motion blur complicates this, because actually you need to expand the "range-of-interest". In the ROP, we expand the range by one sample, under the assumption that there will generally only be useful time samples at shutter open, maybe on the frame, and at shutter close. The assumption fails in your case because you have many sub-frame samples between shutter open and shutter close, and we're only keeping the ones closest to the frame (e.g., frame 9.95, frame 10, frame 10.05). This is why you get *some* motion blur, but only a tiny bit. While unfortunate that you need to know this and need to do something about it, this is easily addressed in the USD Render ROP. You can either change the "Filter Time Samples" mode to "Never", or set "Extra Frames" to 0.5 (or something similar), to further pad the "range-of-interest". I won't post screenshots of your scene but, when I set the ROP as per the attached image, the viewport and mplay match. Edited by robp_sidefx - June 24, 2024 17:14:35 ![[filter.png]]