Is the Rubikon physics engine suitable for S&Box?

With Half-Life: Alyx, Source 2 uses a new physics engine called Rubikon, that isn’t as buggy as Havok in Source (used for example in GMOD).
I’m wondering, whether it’s beneficial for S&Box to use a more reliable and realistic physics engine or if it prevents funny moments like ragdolls getting stuck in a wall and getting literally epilepsy attacks by the physics engine.
Although S&Box isn’t supposed to be GMOD2, do you think it is better for S&Box to use the new physics engine? Would it be possible to lower the accuracy or similar of the Rubikon physics engine to simulate Havok?

Dude, it’s the only physics engine that comes with Source 2. Or you expect that small group of devs are capable of writing their own super-mega-realistic physics engine?


Yeah I’d say so


Not sure how much of the core engine we can manipulate when S&box comes out.
Hopefully we will be able to have control over how the physics engine works.

If not I can imagine the community to come up with a solution for this.

We haven’t started to evaluate it properly yet but don’t worry, I’m sure we can add a few bugs for you


Pretty sure I saw a YouTube video somewhere that was testing the limits of Rubikon.

It’s harder to break, but you can break it.

Players definitely will break it, no doubt.

Looking at some videos of Source 2 physics it seems that they favor props clipping through walls when there’s a lot of pressure, as opposed to Source 1 where they would often freeze up as a group until shooting out in some direction most of the time.

I’ve played Alyx, and accidentally broke out of the map a few times while teleporting. Can’t say how applicable this is to an FPS character controller, but it’s not a good omen.

These two problems concern me that it may be much easier to push yourself through walls in S&box than in GMod. I hope there is a way to tweak this to make it much less likely.

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The new physics engine still has its limitations, apparently the new ragdoll physics are actually worse.

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I’m not worried about it being “more realistic”, that’s something I’ve been wanting in a sandbox game for a long time. However, I’m apprehensive about how resilient Rubikon is going to be in more “extreme” scenarios that are definitely going to happen a lot in S&box. The videos I’ve seen of people testing it using Alyx’s Workshop Tools do not give me high hopes that it will perform much better than Havok if you bang a bunch of props against each other real fast, for example (the kind of thing that doesn’t happen in Alyx, or other less creation oriented games, so they wouldn’t need to make it perform well there)

Optimization wise(as in: how much shit moving about it can handle), Rubikon seems muuuuch better than anything Havok could do, tho

I have mixed feelings about it overall, but I have seen too little to even begin to form a concrete opinion on it. Let’s wait for the release and hope for the best! :slight_smile:

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We’ve probably all seen this video with the glitching ragdolls.
Serverside ragdolls always get disabled in servers unless they have a fancy workaround so I was pretty scared that Source 2 would bring in the end of interactable ragdolls.
That was until I saw this video that garry posted.
The ragdolls are being launched at greater speed than the youtube phyisics test and they aren’t having any problems.
There is a noticeable difference between the model editor and the actual engine running, I wish Garry walked on them using a pill shaped collision box, I’m sure you could climb on them with that.


Thanks, that’s really important.