Particle acceleration is tied to the players framerate

It is expected that the movement of particles from a particle emitter will be approximately unaffected by the client framerate. However for particles experiencing high acceleration and drag, the resultant particle velocity is inversely proportional to the clients frame rate, with particles travelling about twice as fast at 30 FPS than 60 FPS, and half as fast at 120 FPS compared to 60 FPS. This behaviour is unintuitive and presumably unintentional.

Use of acceleration to control particle velocity was necessary to create realistic weather particle effects that are locked to the camera to maintain the illusion of weather even when the player rapidly moves their camera. It does seem to be possible to work around by multiplying the acceleration by the client framerate.

Full Repro:

Create a particle emitter, and enter high values for drag an acceleration such that the particles appear to move with constant velocity. E.g. Drag = 3000, Acceleration = 1500.

Use a program such as Roblox FPS Unlocker to alter your client frame rate between different values.

The speed of the particles will appear to change.


Thanks for the report! We’ve filed a ticket to our internal database and we’ll follow up when we have an update for you.

Please note that filling a bug report does not guarantee that it will be fixed once triaged.


I am in the process of checking over bug reports and following up on some bugs that haven’t received any activity in a while.
Is this issue still occurring or can you confirm that this bug has been resolved?


This issue is currently still occurring, no change in behaviour.


Thanks for the info. When there is an update i will pass it on.