I am working on a 2D game that involves many blocks that stack and collide on eachother and the player. I am currently using Rigidbody2D on the blocks for dynamic collisions but I am not a fan of how the dynamic physics include the "bounciness" in the elastic collisions. Also, there is an inherent push-force as well as other unfavorable push physics that are too "realistic".
I am wondering what is the best way to handle my predicament to remove the bounciness and push elements of the rigid bodies. I've tried adjusting the block's masses and bounciness physics but no luck. Is there a way to set them all as kinematic or disable these realistic effects somehow and still have them collide via rigidbodies? (Kinematic would be great if they were able to collide with each other) Or will I have to create some sort of raycast based block physics handling script? Or is there an even better solution to creating this very primitive physics structure that I am not seeing?
Thanks for any and all help!
The only way I could think of solving your problem, such that you have complete intuitive accuracy, is to write your own Rigidbody controller. Of course you can still reuse the Box colliders.
Once you've decided on a collision detection method and manifold generation working (raycasting maybe), this link details the impulse resolution you need.
Related
I'm looking for a little newbie advice on gamedev strategy and/or approach. I'm working on a game that uses Rigidbody physics in Unity and I've got a character interacting nicely with physical objects in the game world. The thing I'm trying to work through is that there are certain physical interactions that I want to control, but my own attempts to control them are conflicting with what Unity is already (correctly) doing.
For simplicity, let's just say I've got a Rigidbody-based player, and when certain Rigidbody-based objects collide with that player, I want to override where they deflect to. When I detect the collision and apply my own force with rb.AddForce(myForceVector, ForceMode.VelocityChange), Unity is also applying it's own force as a result of the same collision. I also tried setting the velocity directly with rb.velocity = myForceVector, which mostly works, but there are still situations where Unity applies force after I set the velocity so it's glitchy at best.
Other options I've considered are:
Use an additional, larger IsTrigger collision mesh to detect and handler the special type of collision I'm looking for before the actual collision occurs. That might work for slower speed projectiles, but likely will have the same issue for faster collisions.
Change the player to not being Rigidbody-based, which might work, but would require me to code a lot of the other interactions that are already working out of the box with Rigidbody physics.
Use RayCasting to detect when these special collisions might occur next and handle them before the actual collision. This is where I'm leaning currently.
Anyone have a recommended best practice for this kind of thing?
Thanks in advance!
The easiest way might just be to take full control. On the correctly timed press, disable the RigidBody and the Collider. Then just move it yourself to the target location. It's really hard to get precise control over a RigidBody -- every FixedUpdate(), it might be picking up force from collisions, and there can be many FixedUpdate() calls between Update() calls.
You could write a pretty simple coroutine using a Lerp() or Slerp() between the object's current and target position. That way, you could fully control how the object moves toward its target.
Just to follow up... I attempted to "take full control" as suggested in Alex M's answer above, but that ended up making a number of other things complicated in my specific situation. However, his comments about disabling the collider in the original question led me down a different path that ended up working well...
I ended up disabling the collider for the deflecting rigidbody upon impact and setting the velocity of the deflected body directly. That way, I was able to avoiding any additional force(s) applied from Unity while the collision was active. Once the deflected object was on it's way, I just had to reenable the collider.
Thanks, Alex!
I am trying to make some kind of simulation program with Unity. The simulation includes a missile launched from an aircraft and a terrain.
I get the coordinate data required for the movement of the missile from another program using a socket connection.
I created an explosion effect for the missile to explode as soon as the missile and the terrain collided. But the explosion effect is not triggered in any way.
I used the OnCollisionEnter() method to detect the collision, but this method does not seem to work.
The missile has its own rigidbody and collider and The terrain has Terrain Collider, but still no collision is detected and the missile passes through the terrain.
What could be the cause of this error?
EDIT :
I thank everyone for their help, but none of the solutions worked. I solved the error using the OnTriggerEnter method. For this, I also had to enlarge the object's collider a little more.
As mentioned in the comment section above (I dont have enough rep to contribute to the discussion but will provide a solution), you need to enable continuous collision detection. Once you have done that we can move onto the next step.
It is generally bad practice to interact with rigidbodies in update and it can lead to all sorts of strange bugs so I wouldn't recommend it. That being said I dont think it's the cause of your issues. As #HumanWrites mentioned, you are manually moving the position each frame which causes your missile to never actually collide with your mesh. the solution to this is:
rb.MovePosition(Vector3.MoveTowards(...))
The reason for this is that by using the method on the rigidbody, you inform the physics engine that you want to move from one position to the other and you would like the physics to take care of this instead of you doing it directly. This allows it to "sweep" between the current position and target position and detect any collisions that would have happened along the way.
Your missile is moving too fast to ever actually touch the mesh within a frame so you need to rely on the physics engine doing that sweep check.
I've done some research and it seems the consensus is that two particle systems can't collide in unity.
Is there a creative work around or solution to have the effect of having two particle systems collide? I want it to behave like two "streams of water" colliding where each stream is a particle emitter. I can't think of a great solution besides making my own particle emitter, but even then it would be hard to mimic Unity's particle system behavior. I feel like there has to be a way to make that effect though.
Any ideas appreciated, thanks
Create a GameObject--the emitter--that spawns other GameObjects--the water particles--that have Rigidbody/Rigidbody2D and appropriate Collider components. The exact components you will need will depend on the shape of the spawned object.
To avoid performance loss related to instantiating and destroying many objects, you may want to use object pooling for the water particle GameObjects.
In these water particle GameObjects you'll want to implement OnCollisionEnter or OnCollisionEnter2D to handle the interaction between them. You can check for whether the collision is with another water particle inside of OnCollisionEnter*, and interact appropriately.
I have a gameobject with two sphere colliders attached. One has IsTrigger checked and the other not.
I want to execute different set of statements when collision occurs with different colliders. For example I want to play different sound for both different collisions. Is there any way to achieve it?
I tried OnTriggerEnter() but unfortunately it is called for both type of collisions since other colliding objects have triggered colliders. I just thought if we could somehow find out on which collider of the gameobject the collision has taken place we will be able to achieve it.
So is there any way to get through with this?
I have been using Unity for years and faced tons of problems like this, related to bad software design. I hope Unity guys will handle physics more carefully in future releases.
In the mean time, you can use Physics.OverlapSphere and Physics.CheckSphere to manually check if there is something that collides with your object. Remove the collider that you are using as a trigger and use these methods instead of OnTriggerEnter. This is a bit hacky, but this will do the job I think.
Make your colliders visible in the inspector (make them public or add [SerializeField] before it) and then tie in the colliders to the code that way.
Then, in your collisions, compare the colliding objects against your variables that are holding the colliders for you to keep them separate.
To detect for source trigger in OnTriggerEnter, you must use workaround with multiple gameobject hosting trigger and satellite scripts.
Allow me to link to my answer on gamedev SO:
https://gamedev.stackexchange.com/a/185095/54452
I am looking at tutorial where things are defined like this:
planes are sprites with dynamic physics bodies
plane moving is done with actions by following the path
there is contact detection between bullet and plane
bullet is sprite and it has physics body set to be static (which is little unusual in my opinion)
Here is the link to tutorial for more information.
Questions:
When we use actions to move physicsBodies is there a difference how we set body's dynamic property? Because bullet is static but still there is no problem for movement.
When we have situation like this, where we don't need collision detection, but just contact detection, and we can't move sprites (enemies) by applying forces or impulses, what is a good approach? Is this approach correct?
I think this is nice way, but I would like to be fully aware what is really happening when we use this method and are there any drawbacks or possible problems.
There are posts on SO that suggest we shouldn't use actions for moving dynamic physics bodies. I am aware that we can't use this approach in every case. For example this would not work for moving platform with other object on it, because there would be no correct physics simulation between body on the platform and platform moved by action. But in cases like from this tutorial, where we only need contact detection for object that can be moved only by actions (moved along path) I suppose it's not a problem ?
static means that the body isnt affected by physics. That doesnt mean it cant be manually repositioned or moved. So if something is set to static, it participates in the physics simulation, but it isnt affected by it. Think of a plane hitting a mountain. The plane is dynamic, the mountain is just going to sit there even though its participating in the physics. But you could still move that mountain around manually using a position or an action.
Not totally understanding your question, but I'll give it a shot.
You can move physicsBody's manually (using position property or actions), but you need to ask yourself why you're doing that. You typically don't want to do it because they're bypassing the physics simulation. If you're forcing it to move around, what's the point of using a physics body in the first place.. right?
But if your physicsbody is something like a powerup that is totally static, and you just want it to move around in a circle using an action then thats fine. You probably just want to use contact detection for the bullet, powerup, etc without actually moving it around using physics. Nothing wrong with that.