Which version of VRay are you using? And are you using IPR? tyFlow doesn't currently support IPR rendering due to issues I'm hoping to have fixed soon.
Turning to mesh should only be problematic for motion blur if topology changes over time.
Edit: oh I think this is the scene you emailed me right? I will look further into it soon and get back to you about it.
Turning to mesh should only be problematic for motion blur if topology changes over time.
Edit: oh I think this is the scene you emailed me right? I will look further into it soon and get back to you about it.