Introducing Aerodynamic Forces [Studio Beta]

[Rooilo0]

Haha,
yea, It looks like I won’t see it alive. lol

[OH_202020 (OH24_rbLX)]

This is really great for aviation-based games, such as “Project Flight,” and every other game out there that relies on aerodynamics to make their experiences as realistic as possible.

I really appreciate this aerodynamic forces update, I might find it useful for my own games as well!

[Tunnells (PlaySage)]

Very cool! However, highlights are not visible on mobile devices. There’s still a restriction on the number of highlights in a game. Public animations, sounds, and the voice chat API are also not yet available. But hey, at least I can create a kite!

[SFranxisco]

I am very excited to see that the open beta has begun for this. I like the variety of settings that are available to use and modify. This will help with my aircraft developments, a little bit less that I have to manually simulate in code now!

[BlueyHeeler96 (Bluey Heeler)]

I did a quick and dirty test involving spawning 7x7 parts 0.1 studs thick at random orientation. Wind was set to -150 on the Z axis and it looked like real life with how the parts were spinning and flipping around as they flew across the baseplate. Very exciting beta so far.

[Mister_BlueHat (cc567)]

It’s a quick example made to showcase the new aerodynamics. Who really cares if they use a couple deprecated methods?

[TheCrypticRunner (Cryptic)]

This is incredible, it just works out of the box without any finnicky tinkering! Making a parachute attached to a box is as simple as can be and it really shows the strengths of the Roblox physics engine, like the way changing materials can drastically affect how things behave. I can’t wait to see the uses this could have.

[Adam_Hase (Adham)]

I’ve been waiting for this for so long I’m just so happy its finally out in beta!

[ArisNeta]

this is so cool! asking for a friend, though (me), is there also simulated downforce? i’m yet to tinker with it and i want to know beforehand, for car stuff, yknow

edit; also on the topic of cars, would this mess with part-built cars? as in, would it be a better idea to just get the body and union it to make a sort of “collider mesh” for the wind?

edit 2: i tested it, my car was super draggy, it might just be a brick car thing but it seemed impossible to get to speed, i tested with a 10sps headwind and a 1sps headwind, both had the same issues with being able to actually gain speed, the 1sps test obviously a little more successful, but like that’s really it i guess, its pretty odd

[abcabc12Gabo (Sackboy)]

Pretty interesting. Can’t wait for it to leave experimental studio-only beta!

[martytyty2098]

Cant wait to make a realistic War Thunder clone
By the way, it would be nice if they added a feature that allows the local wind in a certain area to be different from the global wind and completely replace it. For example, in one part of the map there is a strong wind, and in another part there is no wind at all.

[LaAeroooo (aero)]

After some more testing, it seems that when trying to use this on a A330neo with a semi true to life weight (approximately 8000 roblox mass if thats accurate) it cant produce enough lift to takeoff unless the weight is reduced or wing surface area is increased by making the wings bigger.

i can send the file as a repro in dms if needed.

edit - turns out the speed was over 3 times lower then i thought it was, since i didnt convert studs to km/s, at the right speed the plane takes off as intended.

[qwertyexpert]

@FGmm_r2

• The aerodynamics model also includes a decay of air density with altitude, similar to the real world. This decay is tuned so that the local air density is 5% of the Workspace > AirDensity at an altitude of 100,000 studs (or 28,000 meters). Below y=0 we assume a constant density value of Workspace > AirDensity.

Will this be configurable?

@FGmm_r2

To balance simplicity with realism, the Roblox Aerodynamic system has a wind profile that automatically scales the horizontal (x-z) wind speed relative to altitude.

Will this be configurable?

@FGmm_r2

With this release, when you set workspace.globalWind, the system interprets that as the required wind speed at a common Avatar’s head height (y=5 studs). The default wind profile automatically scales the wind according to a realistic profile such that at y=0, the wind speed is ~10% of the globalWind property and at y=1000, the wind speed is ~3x the globalWind property.

This is frightening. What if I’m making a sky game? will I have to perform some magic math on the globalWind property in order to get a known global wind, and perform all gameplay above 100,000 studs (and scale the flud density by 2000%) for aerodynamics to work consistently?

[smallpenguin666]

Cool

[FGmm_r2]

Thanks everyone for the great response and interest. We’re already noticing a number of people trying things out in Studio.

Some quick responses to initial general questions / feedback:

Wind occlusion:

Thanks for the feedback / ideas! We are actively thinking of ways to efficiently provide wind occlusion by both static and moving objects. The difficult part is to ensure we figure out how to do it with good performance so we need a bit of time to figure that out. Stay tuned!

Local control over wind:

We definitely would like to make the wind more dynamic and local and are exploring options for that. We hope to have more specific plans soon so thanks for the feedback here.

Exposing more properties / Tuning:

Right now you can control the aerodynamic force by altering the geometry and workspace.AirDensity , we calculate the rest. We are working on debug tooling to help with building aero-enabled mechanisms. If you have any suggestions for what might help, do let us know and we can try to prioritize them.

We will consider exposing control of the density and velocity profiles as we expand the API. Once again, if you have any more specific feedback around how you would like to control these properties, do let us know!

[FGmm_r2]

@abidbmt

the aerodynamics behave very mysterious. The plane starts to yaw into different directions and control unrealistically. This effect is even larger when the air density is set lower than 0.005.

Thanks for trying it out!

Out of the box, the F15 mesh has a center of mass that is too far back for a stable aircraft at realistic air densities. To get more control from the flight surfaces, we increased the air density.

However, a more realistic way to fix this problem is to include some ballast that pulls the center of mass forward making the plane more stable. The new place file (F15Plane_ballast_airdensity.rbxl) included with that example above does just this, and works with the default air density (0.0013).

We are working on tooling to make diagnosing and fixing this kind of problem much easier!
Also thanks for pointing out the deprecation warnings, we fixed those too in both the place files

[kckhem]

@LaAeroooo

it seems that when trying to use this on a A330neo with a semi true to life weight (approximately 8000 roblox mass if thats accurate) it cant produce enough lift to takeoff

Wow! That’s a cool A330neo model! We are trying to improve the aerodynamic model so it generates more lift, preferably without adding too much more drag, in situations like this. If you can share your reproducer with me (@kckhem) it would be super helpful!

[kckhem]

@ArisNeta

is there also simulated downforce

Great question! Yes, you can use this to generate downforce on cars by adding wings!

@ArisNeta

my car was super draggy

We’re sorry to hear your car didn’t work as expected! We have tried the aerodynamics on a variety of cars but haven’t seen this issue until now. We’d be happy to take a look at it and figure out what is going on, can you dm a reproducer to @kckhem?

[abidbmt]

Great! I’m very excited to see the potential of this feature as I would like to use this to make a highly realistic Simulation game similar to DCS (Digital Combat Simulator). Btw when looking through the model, I noticed that there is a script called “SetAero” which has some lines of code that aren’t useable. Are these features that are work in progress?

[Widgex]

Wow an aerodynamic system! This is really cool.

I have some requests that would really help make this system useful for the game I develop:

Could you allow us developers to tune the air density vs height in a number sequence + also the wind system (both relative or altitude based). Making the system more modular means that more can be done (like other planets atmospheres or games like KSP).

Also I would appreciate a readout of the current air density percent at a part location, this would be useful for simulating the power loss of piston engines at higher altitudes.

Providing the aerodynamic force as a vector 3 acting on a part would be useful for calculating things like re-entry heating. Separating them between lift and drag may be useful. (If you all go about this could you please add the total force acting on a part as a vector 3? I really need those forces to change the size of a cylinder to simulate tire pressure.)

Also when you add the water force model could you allow us to modify the density of terrain water? I use 21.952 roblox density as 1 g/cm^3 and I currently have to weld 22 parts inside eachother to get the correct volume, buoyancy, and mass. If this isnt added I would have to detect if a part is inside terrain water and disable the fluid simulation on it and run my own.

I did give this system a quick test and was very impressed with how easy it was to run and that the propeller I made just worked right off the bat.

Edit: I had time to test this system. Happy to know the aero is well done.

I had a problem when testing wind because horizontal wind would not cause any lift on the system.

I could not replicate the lift model creating unrealistically low lift, from what I have tested with parts it seems to work just right. Perhaps you all were referring to different shapes or unions/meshes?
Ill leave a download of the aero test model I made:
AerodynamicsTest.rbxm (9.7 KB)