I can already imagine creative uses for this
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With how many people are reporting they would have been affected, were there any discussions about showing a warning if you create a CustomPhysicalProperties with density as exactly zero?
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Oh nooo! So unfortunate to see.
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Yes! We are planning on adding a warning message whenever there is clamping for either the minimum and maximum values of any of these physical properties. We will update this post when that’s implemented 
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Just don’t use hydrogen. Balloons are gonna be much easier depending how it will float.
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Do you have any plans to update Physical Properties further?
I suggest adjusting the Maximum Part Density.
As illustrated in the following image from rojo.space,
PhysicalProperties currently only uses
float32s, ranging from -3.4 * 10^38 to 3.4 * 10^38.However, I’m unable to set the density above 100 at the moment (0.0001 ~ 100).
I need the ability to set the density higher than 100 to implement the “Physical Time Scale” feature in our studio’s game.
When the TimeScale is less than 1, it becomes necessary to increase the density, as shown in the images below.
When dealing with a part that has a density of 7.85 (Metal Density):
- If the time scale is 1, the part’s density should remain at 7.85.
- If the time scale is 0.1, the part’s density should increase to 78.5.
- However, if the time scale is 0.05, the part’s density doesn’t increase to 157 but is limited to 100 due to the current maximum density constraint.
Additionally, I would like the ability to occasionally set Friction above 2, as well as increase FrictionWeight and ElasticityWeight beyond 100.
I hope Roblox will consider expanding the range of physical properties’ clamps, not just for the minimum density values.
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this actually is a valid reason to make an important post, as games that will use these soon-to-be-unreliable values will experience unwanted changes with their part systems.
on another note, i’m happy those values are being implemented. floaty parts are gonna be useful for making planes in the future, and don’t even let me speak on about how nice obbies will be with these mechanics in place. i am an enthusiastic scripter and making custom objects with variety is always fun, but when something new steps into place i always have ideas about it!
great to see something new once in a while, but make sure to address some old bugs in the process
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Would it be possible to let us opt-in for this updates in live servers first, like a boolean property in the workspace? We got multiple games with lots of A-Chassis, this would allow us to assess the impact of this update on our games.
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As a developer who really likes messing around with beta features, I’d really love an early opt-in for this!
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this would make for a funny troll command
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This for sure, the whole point of the 0 density function of A-Chassis is to make parts weightless so your body parts/meshes don’t affect the weight of your car, and in games that don’t utilize fluid forces, parts floating isn’t exactly going to be a concern (at least that’s what i can understand with parts being lighter than air causing them to float, since if there’s no forces at all that shouldn’t happen, right?). I’d like to be able to test the waters with this change to see if it’s even worth my time to start changing hundreds of initialize scripts to be compatible with the new limits, since right now all we know is that it will happen, how it will affect things in theory, but not how it will actually affect our things, since we can’t test it for ourselves beforehand.
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Setting the density to 0 does not actually set the density to zero, it gets clamped to 0.01 today, so parts are not weightless. You can set the Massless property to true, which, under specific conditions, prevents parts from contributing to assembly mass. However, Massless is independent of the density, and is ignored when the part is its own root part.
If you want to set the density of a part to something very low, but future proof it against changes to the density lower bound, we suggest setting the density to something at or above the lower bound, currently 0.01, and soon 0.0001, rather than setting the density to zero and relying on clamping behind the scenes. That way any tuning you do that is affected by part mass will be insensitive to future changes in the clamping.
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Most of the A-Chassis base code was written somewhere around 2017 or so, back when Massless wasn’t a property yet, that is why 0 density was opted for, regardless on if it was truly 0 or not, there are external scripts that enable massless for all parts, however i am unsure if a functionality like such was ever included inside the actual Initialize script, still, the ability to be able to gauge what kind of an impact this update will have on our stuff (especially since A-Chassis is heavily used inside of “slot” communities that likely don’t know anything about this change (or how to edit their existing a-chassis installations to not be affected)) would be greatly appreciated, since this will have a massive impact on things, and given that, an opt-in preview be (likely as a beta feature) would be of huge help, not just for developers that use it, but also for the car community as a whole.
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this update sounds super cool, cant wait to try it out
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We will update this once the change is live
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wow i can’t wait to play physics, maybe we could create hot air baloon? if possible, can’t wait 
Is this change still going live today? I just checked, it’s still not happening yet.
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Hi Everyone,
Due to too many experiences still clamping the minimum density of parts incorrectly, we will release this change through a 3-phase rollout workspace property. We plan on enabling opt-in for this feature by End of March.
Also, to assist with this incorrect clamping, we have added a warning message in Studio for any experience that clamps any Physical Properties to their minimum or maximum values. This warning message should help you know which script(s) are doing this and need to be adjusted.
Thanks,
M0bsterLobster
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Please refer to the update - I apologize for the delay. We had hoped a 3 phase rollout wouldn’t be necessary.
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