Real-Time Physics in Source

G

Guest

Guest
This was said in the Valve Q and A thread in the forums (see below), and implies that real-time physics do not actually exist in the Source engine...but who's to say what they have limited the number of constraints to on a wooden plank for instance. As far as we know, there could be over 100 constraints on a 4' wooden plank, just waiting to be shot at, and splinter.

It's up to the designer. They can be created as a single contiguous model for physics, or created as a group of models and attached together with various breakable constraints. Or you could swap out a single model for multiple parts on breaking, which is more like what we did in HL1. The break points are where the constraints are, so unless you have additional constraints up and down the leg, the best you'll probably get is the entire leg breaking off and the table tilting over/falling, etc as expected.

Yahn

-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Thursday, July 10, 2003 12:45 AM
To: [email protected]
Subject: Here's a new question for you!


In the tech-demo movie, we all saw those wooden planks that were shot to pieces, and the structure fell very realistic.
I wonder if all, or maybe just some of the wooden objects in the game, like for example tables and chairs and so on, are build up of individual wooden planks, or are they completely solid objects?
That is, could you for example shoot two legs off at any position from a table, making it slant/tilt a little or very much depending on how much you cut those legs, or maybe shoot a bit off from all legs on a chair and thereby lower it.......OR do they react as in other games, that is they break apart as a solid object? Or is it somewhat inbetween, that you can cut off a leg, but only at one specific position?



I guess this means real-time physics really don't exist in source. Looks like you can't shoot it anywhere and it will splinter anywhere. Major let down #1.
 
:/ i thought that was the whole point of Havok - real-time physics
 
i dont think thats what he meant. i think he was saying that if u dont want it to be broken u can. and if u want it to have multiple breaking points u can. we'll just have to wait and see
 
Yeah, but I guess the world has to be made up of "Breaking-Points" where if shot at (in or around the same spot), will break the same way everytime. Hopefully, there will be many many break-points on objects.
 
Source uses an integrated real time physics engine called Havok (www.havok.com), which they have heavily modified themselves.
Yahn was simply noting that yes it would be possible to have 100% physical properties on the wood with regards to how it breaks or splinters (like we saw at the beginning of the E3 video) but on the other hand the level designer may acually choose to use a similar method that was used in HL1 which is slightly more restrictive, but in some cases more appropriate.
 
Im sure they put lots a breaking points in wooden planks and such. Wouldnt it be hard to make something break exactly how you shoot it?
 
Originally posted by rollthedise
I guess this means real-time physics really don't exist in source. Looks like you can't shoot it anywhere and it will splinter anywhere. Major let down #1.
Click to expand...
Im not sure what you were expecting? Do you mean something like Red Factions Geo-mod technology only applied to absolutly every physical object in the game?
 
No no no, I didn't post that, I copy and pasted what waws said in the Valve Q and A thread.
 
the table tilting over/falling, etc as expected
Click to expand...

i.e. as in real-life, which funnily enough has real time physics

The question wasnt about physics, it was about the realistic breaking of a table leg. Yahn answered in relation to the table breaking and only mentioned physics as a secondary effect at the end of his answer.

You jumped to a conclusion which is wrong, the real conclusion is that table/chair legs will break off completely when broke and the object will react with real-time physics to this. It is possible to program more than one breaking point, and the object will react with real-time physics to each one of these breaks.

*EDIT* sorry, didnt realise you didnt ask Yahn this
 
Originally posted by rollthedise
No no no, I didn't post that, I copy and pasted what waws said in the Valve Q and A thread.
Click to expand...
Oh sorry, I thought that last bit wasn't part of the original message, thought you just forgot to turn of the bold tag.
 
They've stated that the physics engine is only designed to calculate for ridgid objects, and from what I've seen, it does an incredible job, giving a degree of interactivity unprecedented in a video game.

The kind of physics you're asking for--where a table leg will break at the point of impact in real time--is probably beyond the computational powers of most desktop computers if it were applied to every object in the game.

Look, folks, Havok is just a physics simulation, not real life!
 
I guess this means real-time physics really don't exist in source. Looks like you can't shoot it anywhere and it will splinter anywhere. Major let down #1.
Click to expand...

Jesus.

What are you talking about?

How is this a let down?

The wood still splinters like wood, and as it was said, you can make the model from seperate parts, so that if you shoot out a leg (or if it's set up to do so) or part of a leg, it will slant or fall over. You really need to learn some basic modelling or mapping skills before you go saying how something like this can be a let down.

In the original HL, if you shot the walls out from a building, the roof would stay in the air, unless you scripted it to fall down. Now, if you set up something similar in HL2, the roof will crumble and fall as soon as you shoot out one of the walls, and it will break as the real material would do.

If you really wanted to make a table with the amount of detail you were talking about, then nothing is stopping you, but it would add minor lag to your game, for such a small effect.

Secondly, why do you put your expectations so high? I mean, sure I'm tinking the game will be great, I've got big plans for a mod based on the materials and physics engine, but putting the engine on the plataeu (you were asking for real life, real dynamic world reactions from something like a table that's made out of wood, without any special pre-planning or scripting, that's near damn impossible with current technology and normal home pcs) is just silly. You're heading for a fall at every post unless you lower your expectations just a notch.

Remember. It might be Half-Life 2, it may be a great, new, advanced, engine, and it may be made by Valve, but it's still a GAME, not a real world simulation.
 
Electrico, I suggest that you read all previous posts, then you'll come to the conclusion that it wasn't rollthedice that wrote that. He just pasted it from another thread or letter or something. There, now I've said that :)
 
I know, I read that after I posted.

So just take it as I'm aiming it at the person who wrote it.

Whoever the idiot was.
 
It was TheRocker132 / Guinny . He since apologized for going off the deep end.
 
Originally posted by Tamora
Electrico, I suggest that you read all previous posts, then you'll come to the conclusion that it wasn't rollthedice that wrote that. He just pasted it from another thread or letter or something. There, now I've said that :)
Click to expand...

My SN is rollthediSe! you might think im stupid or sumthin..butit's spelled eith an s because that's my last name :afro: hahashahaa..i know, it sux my ass
 
rollthediSe: haha, well I noticed that one after i wrote it ;)
But what the hell, it's not like this forum is overcrowded with people having nicknames that makes sense hah.
 
Physics is not part of the destructability of an object.
That is science/chemistry.

Physics is when object collide or they roll (like a barrel) oranything having to do with gravity.
 
"So if something looks like wood, sounds like wood, scrapes like wood, floats like it, and if you shoot it it will fragment like wood."

I dont think valve is ****ing with us.
 
well, at the end of the day, when you've played HL2 and sprayed your shorts several times. Who gives a ****
 
[OT]BWMASTER - I've sent you a PM[/OT]

Erm... yeah.
 
OH NO! the source engine sucks now! It wont break wear I shoot it! omg.. im not buying HL2 now.. screw that... bah.. All I wanted was breakable wood were i shoot it.. man.. this sucks.. HL2 sucks.. the world sucks... im going to commit suicide now!

....:rolling:
 
Read the beginning of ign 's preview.

http://www.ign.com

Has some cool info. For example it says in the preview that when you scrape a barrel for example, with the manipulator on a brick wall it makes realistic scraping noise with sparks and evreything.


I dont think anyone is going to notice if the wood broke exactly at the right spot because you can't really tell. The splinters are too big.

Guyz it's still a revolutionary step in gaming and If it looks at least as good as in the Pre Alpa E3 demo then I think people will be happy.
 
I have a few comments to make in terms of terminology. I didn't see it in this thread as much as in the prior ones, but....

1.) "rag-doll physics" only applies to characters and monsters and things of that nature. It is a way to simulate the limits and bending of joints so that bodies will behave accordingly. Thus, not applying to rigid bodies

2.) To say that because the wood has defined breakpoints, that HL2 does not have real times physics is utter BS. It has real time collision detection and response for all objects in the game. You remember the part of the e3 video where the body went plowing through the table loaded with crap.... tell me thats not real time physics.

3.) To calculate stress points and the effect of a bullet hitting a wooden plank is very computationally intensive. How so?? well first of all, you would have to run the simulation with about a 1/100th of a second interval, using the elasticity of the board of wood, and knowledge of the direction of the grain, as well as normal physics conditions, such as collisions and friction. All this would have to be done either on a very high resolution mesh for accuracy, or with some sort of parametric mesh where an equation defines it surface.

So it finally passes the breaking point. The geometry would automatically have to create new faces and verticies to represent exactly how it broke. Frankly, its just not worth it. THis little scenario would take about an hour to complete, for about 1 second worth of gameplay.

4.) "So if something looks like wood, sounds like wood, scrapes like wood, floats like it, and if you shoot it it will fragment like wood."

does it look like wood? yes
does it sound like wood? yes
does it scrape like wood? yes
does it float like wood? yes
and does it fragment when shot like wood? yes

at no point did they lie about anything related to the wood.

Adam
 
Who the **** ever cares jesus!? You wouldn't even be able to tell that there are determined breaK points when playing because you'll be having so much fun so just stfu already and stop being so technecally anilitical. It has been stated many times that "people set their standards way to high" especially for a game. It will be atleast another 5 or even 10 years before we see physics in games where we could break things exactly where we damage them and we will have more powerful computer technolgy. For now just enjoy the technolgy we are being given which should be enough to please most everyone.
 
Good point guineapig but please watch your language and temper.
 
I thought people would realize this when they saw the watermelon get shot...
 
I read only the first post...

But I seriously don't think some of you understand what havok does.
 
Has anyone played the Chaser demo?

When you shoot at wooden planks in this game, it breaks exactly at the point you shoot at, so I'm sure you can do the same in HL2. This isn't exactly a big deal. Even Max Payne (the original) has this mundane feature.
 
Originally posted by chili pepper
Has anyone played the Chaser demo?

When you shoot at wooden planks in this game, it breaks exactly at the point you shoot at, so I'm sure you can do the same in HL2. This isn't exactly a big deal. Even Max Payne (the original) has this mundane feature.
Click to expand...

Who said HL2 doesn't have it?
 
It's definitely in there. It's in the Max Payne PC demo and the full game. I don't know about the console versions.

You can see it in the PC demo levels for example (I think its a hotel). You climb out onto the ledge of a hotel and see this boarded up window. Wherever you shoot or break the boards they will break at the point that they are struck. Pretty mundane stuff.
 
i am pretty sure those are made of several different planks of wood/ predetermined but i could be wrong
 
Can you link me to the chaser demo you played? I played one but the boards didnt break , had good water FX though.
 
You must log in or register to reply here.

Similar threads

Terminator
Long time...
Replies
16
Views
1K
Xtremecherry95YT
Xtremecherry95YT
Krynn72
You guys, what the **** is up.
Replies
11
Views
2K
Tollbooth Willie
Tollbooth Willie
Tollbooth Willie
HL2.NET HORROR SLAP
Replies
7
Views
2K
Tollbooth Willie
Tollbooth Willie
Lizardizzle
2019: The year of Half-Life SFX videos
Replies
4
Views
2K
Ennui
Ennui
Tollbooth Willie
To Those That Stand, Those That Fell
Replies
6
Views
2K
Tollbooth Willie
Tollbooth Willie
Back
Top