Moving All Games to PGS Solver on March 4th, 2019

We are switching all Roblox games to use the PGS solver on March 4th, 2019

Currently, games owners can set the Workspace property TemporaryLegacyPhysicsSolverOverride to True to use the legacy spring solver. However, on March 4th, 2019 this will no longer be the case, and all games will be switched over to the PGS solver for physics simulation.

Over the last year, we have reached out to the developer community to discuss why we are doing this and to give everyone a chance to modify their models and games so they work as desired with the PGS solver.

Please look over the following information if you still have questions or need assistance migrating your games.

Legacy Solver Users: You still have a decent chunk of time to make this transition for your games. The physics team is ready to assist. We have already collaborated with many of you to make model adjustments or utilize alternative models designed to work optimally with the PGS solver. Please take advantage of this time right now to make sure your games work with PGS. Feel free to create separate threads on the developer forum asking for help and advice (and make sure to tag Timobius).

We really appreciate everyone’s huge effort to reach the awesome level of PGS adoption we have today - approximately 98% of gameplay time uses the new PGS solver!




While I’ve converted all my games to PGS by now, I applaud the early warning being given out to developers which still rely on this behavior.


Press F to pay respects to the spring solver.

It was a marvelous system for its time, developed in part by Mr. David Baszucki himself!

(Assuming this blog post by @Shedletsky is anything to go off of)


Thanks for the heads up!
Confident that the current PGS problem we have right now, will be fixed before this happens.

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You’ve done us well, spring solver. Rest in peace.

The 5-month advance notice is greatly appreciated. This is a large time frame for us to begin converting things over. Might I suggest a pin or banner, since this is one of the more important things to take note of?


Hoping to see some improvements up until that point. Still running into problems with how PGS deals with changes in surfaces / collisions.

Been running through possible solutions of switching cars from Legacy to PGS, all day. Came up with a few, but they’re far from being viable yet.

If anyone wants to play around with my test creations and pose possible solutions, you can test them here.

All of my cars are using Hinge Constraints, rather than Hinges.

Feel free to go for top times.