I have a Niagara rain fx. To avoid TSR smearing, I check ‘Output Depth and Velocity’ option for rain particle material. Then an artifact appears.
As you can see in image below, the rain particle seems to bring out the color of nearby pixels along its path. It’s very obvious at the edges of background objects. Uncheck ‘Output Depth and Velocity’ works but the rain become blurry under TSR and this is not what i want. When the camera moves, the artifact becomes more obvious and unacceptable.
I tried to decrease rain’s falling speed. The artifact reduced a bit, but still exist.
Is this expected for fast moving objects? Or any solution to this? Thanks.
This is the expected behavior when using temporally blended effects.
This post talks about why transparent objects and motion blur / temporal blending don’t play nice together.
The short of it is that accurately compensating for motion with TSR and/or motion blur requires accurate depth and velocity buffers. There is only one depth and velocity buffer, so it is only possible for it to be accurate for either the foreground or the background element, and the greater the discrepancy in depth or velocity the worse the artifacts become.
