04-05-2019, 04:33 AM
Hey,
So I looked at your file and the behavior is expected. Here is what's happening:
Because you have caching disabled, there is no information saved to RAM concerning particles states at a timestep other than the current one. So if you were to scrub backwards in time, the simulation would have to start fresh to get to any prior frame.
Because you're rendering with motion blur, VRay is essentially triggering that behavior itself. So if you render frame 10, in order to get a proper motion blur interval, VRay is querying tyFlow and saying "Could you please tell me particle transforms on frame 9.5 and 10.5" or whatever, to get the motion blur vector. As soon as tyFlow is asked for the prior frame (in that example, frame 9.5) it resets the sim to calculate that data, then continues forward to get to 10.5 or whatever.
So in your case there are two solutions: enable caching (which will take a lot of RAM, of course), or export your particles to another history-independent format like PRT, tyCache, etc...and render the cache instead.
Hope that makes sense!
So I looked at your file and the behavior is expected. Here is what's happening:
Because you have caching disabled, there is no information saved to RAM concerning particles states at a timestep other than the current one. So if you were to scrub backwards in time, the simulation would have to start fresh to get to any prior frame.
Because you're rendering with motion blur, VRay is essentially triggering that behavior itself. So if you render frame 10, in order to get a proper motion blur interval, VRay is querying tyFlow and saying "Could you please tell me particle transforms on frame 9.5 and 10.5" or whatever, to get the motion blur vector. As soon as tyFlow is asked for the prior frame (in that example, frame 9.5) it resets the sim to calculate that data, then continues forward to get to 10.5 or whatever.
So in your case there are two solutions: enable caching (which will take a lot of RAM, of course), or export your particles to another history-independent format like PRT, tyCache, etc...and render the cache instead.
Hope that makes sense!