Problem with single blurry frame?

Question

My animation is almost perfect, except for one frame that has a kind of Gaussian glow:

Here are the stills:

Frame 31 is crisp

Frame 32 is blurry

When I turn off motion blur, the glow goes away, but I still want my animation to have motion blur. I don't see anything that would make that one frame different from the others (the camera doesn't move any faster, for example). How can I prevent this problem? Thank you!

Answer 1 · 2019-10-28T20:05:24Z

Kent Trammell replied October 28, 2019 8:05pm

Hi aubrie - Are you using Eevee or Cycles?

Answer 2 · 2019-10-29T01:10:32Z

replied October 29, 2019 1:10am

Hi Kent! I'm using Cycles (as Grant recommends since the smoke texture doesn't show up in Eevee). Thank you for your reply!

Answer 3 · 2019-11-05T22:20:35Z

Kent Trammell replied November 5, 2019 10:20pm

Hmm..I'm not sure what could be causing this. Could you provide a download link to your .blend file so I can take a closer look? Best way to do this is by uploading to Dropbox, Google Drive, or equivalent service and copying + pasting the share link here.

Answer 4 · 2019-11-06T04:34:45Z

replied November 6, 2019 4:34am

Does this link work? Thanks, Kent!

Answer 5 · 2019-11-13T23:03:31Z

Kent Trammell replied November 13, 2019 11:03pm

Sorry for the late replies. For some reason I'm not being notified about your responses.

Thanks for supplying your .blend file! After troubleshooting the scene I was able to fix the bizarre blur on frame 32 by changing the Position parameter (in Cycles render settings) from "center on frame" to "start on frame".

Answer 6 · 2019-11-17T02:09:12Z

replied November 17, 2019 2:09am

No worries about the late replies, and thank you so much for that solution! It worked perfectly! :)