Godot collision problems

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waporwave

I've asked around before, but I think it would be better to put this on the forums, instead of something like discord.
Essentially, what's up with godot's collision? Seriously it's been very janky for me in tons of ways and I've not really found satisfying solutions. For example, in 2D making a slope tile barely works because the player consistantly collides with the edge of the slope somehow stopping all momentum. In 2D and 3D, any objects going (relatively) fast at all will clip through walls. The most common answer I've gotten is "just don't have fast objects", and look I'm not going to be stubborn or pester people about it, but I don't think having thrown objects or planes in a videogame is that crazy. Since it's not really been possible in my experience, I'll move onto other things, but I would really like to see that be more easy to do.
Also I know that 4.0 will be bringing a lot of changes, but things on the tracker like continuous collision detection (which I've heard on forums has been broken for several years) don't seem to have been changed yet, even as 4.0 is getting closer. I even considered learning how to compile godot myself, but I haven't seen any public contributions about these issues.
I don't mean this post to be rude, I just like having fast, and smooth moving objects in my games, and godot doesn't make that easy right now. I'd like to hear your thoughts,solutions or insights, on the matter, and where godot is going in the future. Sorry if this is formatted wrong here, it's my first post.

Megalomaniak

waporwave For example, in 2D making a slope tile barely works because the player consistantly collides with the edge of the slope somehow stopping all momentum. In 2D and 3D, any objects going (relatively) fast at all will clip through walls. The most common answer I've gotten is "just don't have fast objects", and look I'm not going to be stubborn or pester people about it, but I don't think having thrown objects or planes in a videogame is that crazy.

Sounds like you might want to increase the Physics FPS setting in project settings.

the_maven

Friend I think would be easier to you get help in here with you could be more specific about a project you are doing so everybody could you in the right direction, being it code or any other thing.

About physics, Godot is a very capable game engine.

Start a project of your own or if you already have one, when you find a problem just open a post here describing your setup, the script your using or you need, what is the goal you are trying to achieve and you'll find help here.

You only need to describe the problem. And have a little patience because is not always that the more experienced ones are online.

waporwave

the_maven
I appreciate that, but I've had plenty of projects with specific collision problems, the thing is that I never really got any solutions. The question isn't specific because I'm not wondering about a specific physics problem, but more of the future of godot I guess.
The three answers that I've gotten to all of these problems have been "Increase physics fps", "Code your own solutions", and "Code around the issue".
- Increasing physics fps didn't work in most cases.
- Coding around the problem, or rather making a game that doesn't include these cases is fine, but it's what I'll already be doing if it doesn't work, and what I have already been doing.
- Coding my own solutions is also a fine suggestion, and even though I'm not really skilled in this area, it's probably what I'll try next time I encounter these problems.
That last one though, also brings me to what Pixophir had mentioned, swept volumes. If im not mistaken, this is exactly what the Continuous Collision Detection feature is supposed to do (along with a ray casting option) to minimize these problems, which currently is not working. My question was more about things like this, engine features. Do we know if it will be fixed, say, this year? Or should I not bet on it? Since I'm not super skilled with doing my own physics, projects that run into a lot of these problems, for the most part I just don't work on. I have other things to do, other things to create, but it does present a barrier to what I'm able to create by myself.
Oh well, maybe I'll create some of my own solutions here and there, but I'll mainly avoid planes and the like for now.

duane

The only way to have perfect physics would involve a lot of extra processing time, and most projects don't need it. If you've got a corner case, like something really fast, you're going to have to do some extra work to deal with it passing completely through an object in one frame. That's been true with all three of the engines I've worked with. You either make bigger collision shapes or code to predict when an object is going to cause trouble and deal with it directly.

Pixophir

Megalomaniak
Haven't looked into how Godot handles collisions yet, but what about swept volumes ?

Apart from that, there are quite some reasons why objects fly through each other, including choosing the wrong node types. Without more information about what kind of objects and what kind of movement it is hard to say what's going on.

Megalomaniak

Sure, but increasing Physics FPS and giving it more frame opportunities to register a collision is a start. Comes at an obvious cost to either performance or minimum spec requirements.

Megalomaniak

waporwave Do we know if it will be fixed, say, this year?

Will be added or fixed in time, but no eta. Godot is going to return to developing it's own physics engine rather than relying on middleware for it.

Pixophir

There are solutions. But without more info (the scene, a vid) there's just too much speculation.

cybereality

There are a few rough spots, but collision generally works fine. At least I haven't encountered any major problems, and I've done a bunch of tests. For general movement, at the speeds realistic for a human character or vehicle, there are really no problems. For fast projectiles, most games do not use a physics engine, but rather ray casts, as physics don't usually work well for like bullets and stuff like that. Ray casting also works fine. I've had a few issues with collision normals, but the hit detection is good, and there are ways to recalculate the normal. I haven't tried CCD, but that would be one other option to solve the issue. Or, depending on your game, you might need a custom solution (such as a military sim where you need real world accurate ballistics). But all the tools are there, and as far as I can tell, they are all working. Maybe if you could explain more about what you think doesn't work, or provide a video or code, I can look into maybe what is wrong.

cybereality

Godot Physics already works, you can use it in 3.x today (there is a switch in the project settings). However, it's not feature complete in terms of everything that is included with Bullet. But for the basics, like for a platform game, it should be fine.

waporwave

I guess I could try out the other engines? I didn't know that the default wasn't godot's own.