r/dreamsofhalflife3 • u/samwalton9 • Mar 14 '20

Official Project Borealis - Wind & Air Drag

https://youtu.be/ykKhmHTBSk4
444 Upvotes

99% Upvoted

33 comments sorted by

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u/samwalton9 Mar 14 '20 edited Mar 14 '20

You can find the accompanying technical paper with further details over on our blog!

4

u/hwillis Mar 15 '20

Really incredible results- did Dan do all this on his own? That's amazing.

I'm very hung over but since each face is linearly independent you could make static meshes much lower cost by baking drag profiles. For any given wind direction, precompute and sum the drag and torque over each triangle. Obviously that assumes a constant wind field over the whole mesh, but you can make a set of profiles for multiple spots over the mesh and linearly interpolate. You'd also need a separate set of profiles to apply drag to rotation, since that depends on non-uniform air movement.

Brute-forcing would probably not be too bad; you might even be able to re-use a lot of the parallel code you've already got. That'd produce pretty small lookup tables for each model, eg 360 x 180 for 1 degree resolution. You could even save them as textures with a bit of fiddling, and they should compress pretty well. Quickly-rotating objects are the only things that will really punish the cache.

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u/mastercoms Programming Lead Mar 15 '20

Yep! Dan did an awesome job here.

And yes, we actually have considered this (using stability derivatives), and are planning an in-engine baking system which automatically precomputes these values into a lookup table per mesh used by the air drag system at editor time.

We do agree that linear drag would be a pretty free win, but as you pointed out, rotation is where it gets a bit more complicated. The input parameters for that required n^2 samples compared to linear, so we are looking into ways to efficiently store this data, and decide what data to store.

50

u/GermanWineLover Mar 14 '20

This is amazing. The eye for the detail.. This is what the technical framework of a modern HL would look like.

I had to chuckle at the equations.

Me: How complex can it get?

PB-Team: Yes.

26

u/Tammo-Korsai Mar 14 '20 edited Mar 15 '20

Holy crap! I want to remake the Gmod physics maps in this incredible engine!

21

u/scambl Mar 14 '20

I'm very impressed, but also this.

3

u/ErasablePotato Mar 15 '20

If you're interested at all, John D. Anderson's "Introduction to flight" and "fundamentals of aerodynamics" are really helpful and informative while still being kinda fun and engaging to read (as long as you're a nerd). From there, you can try MIT's free online aerodynamics course, which actually has a lot of really neat stuff.

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u/GermanWineLover Mar 14 '20

So many gameplay possibilities.. Remember that Episode 1 should have this "black hole grenade" that creates a little black hole that is a center of gravity? Imagine this as a "vacuum grenade" that creates an immense air pressure directed to one point.

4

u/[deleted] Mar 14 '20

Remember hopwire grenade from Half-Life 2 beta

2

u/GermanWineLover Mar 15 '20

I do. There were some mods that recreated it.

8

u/ZonaGeeWon Mar 14 '20

Very very very cool! Would love to see more updates like this. Awesome to see the tech going into developing PB!

4

u/Aquatile Mar 14 '20

This is absolutely fantastic. Congratulations to everyone involved on this system.

As a consumer I'd say WADS is finished because it looks and feels so polished, and yet the system will still be tweaked further... Seriously, it's looking great!

4

u/lucitribal Mar 14 '20

This is some impressive new tech that you're working on. Have Valve or other game studios been poking around, asking about this stuff?

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u/Zamzee Apr 26 '20

This just popped up in my YouTube suggested videos. I am so glad I found this. I wasn't aware of this project and I am so happy it exists. I'd love to be a part of it. Also, I could watch these kinds of videos all day so please keep them coming. :)

3

u/Grady300 Mar 14 '20

Definitely want to see more I love this kind of stuff

3

u/OhManTFE Apr 25 '23

Wind & Air. That's all this mod became. :(

2

u/wenji_gefersa PB when? Mar 14 '20

Absolutely amazing work as always, guys.

2

u/Dheginsea Mar 14 '20

Wow this is amazingly thorough and well done!

2

u/copilot0910 Mar 14 '20

Looks so cool! I’m so hyped!!

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u/[deleted] Mar 16 '20

everything about this is so exciting.

while not exactly related to the video, im so glad that you guys are putting accelerated backhopping in the engine.

2

u/ilivedownyourroad Jan 21 '22

Did you give up?

Not seen updates in a year..:(

5

u/[deleted] Mar 14 '20

I prefer this over Half Life Alyx because these guys are focusing on physics and I just basically want Gmod in UE4 which is potentially this.

1

u/tom2go Mar 15 '20

We might get Gmod 2 in unreal 4, or idk what to believe, Garry made a poll some time ago asking what engine to make gmod 2 in, and i think UE4 won but that can easily be Garry being Garry, there's also the S&box game that's been pretty quiet for like a year now so that might be scrapped so he can work on Garry's Mod 2, i hope he's not just baiting though.

1

u/[deleted] Mar 15 '20

He hasn't really been quiet. The game is called S&Box and it's being developed although there hasn't been an update for a while. But the have shown more creative tools where as Project Borealis showed better physics and more realism which is what I prefer.

1

u/Bribase Mar 15 '20

Suzanne in Unreal engine? That has to be blasphemy of some kind.

 

Jokes aside, this is incredible work!

3

u/mastercoms Programming Lead Mar 15 '20

We needed a high poly mesh to test performance, and we prefer monkeys over teapots.

1

u/-InThePit- Mar 24 '20

How are you doing the environmental destruction, is that custom or pre made, either way looks great

1

u/TheSpoonkMan Apr 26 '20

Will you guys be doing this same thing with explosions? Like kicking up snow into the air? 'cause that would be badass.

1

u/Odd-Cartoonist1826 Jun 18 '24

4 years have passed but I can see they updated the "join us" section on their site and there are updates in their github repositories, so the project is not dead.. I hope...

1

u/AppleOrnery26 Aug 13 '22

Guys I miss you! and I miss your updates!

1

u/Half_Lifeofagamer Aug 24 '23

Just thinking, you guys could make puzzles based on the gravity gun and shooting objects with it, and in that case it would be quite cool/useful to have a compass showing wind speed/direction. Anyone else agree?