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.
Related
https://docs.unity3d.com/2021.1/Documentation/Manual/CollidersOverview.html
While getting some basic collision detection set up I referenced the official docs on the matter. Unfortunately, this left me more confused than when I started.
I made a simple scene. In this scene I added a sphere with a sphere collider (non-trigger) and a Kinematic Rigidbody. A script moves this object on the X axis when played.
I then created cube with a box collider (non-trigger). This object has no rigidbody or scripts attached.
Looking at the chart in the documentation linked to above, this should fall under the Static Collider and Kinematic Rigidbody Collider interaction, which should not create collision events.
However, if I add a OnCollisionEnter() to the sphere, it will call this method when the objects collide. Without physics they both continue on their way, otherwise oblivious to each other.
My concern then is that either the documentation isn't entirely correct or I have a fundamental misunderstanding of what it is telling me.
What's going on here?
I've been having difficulty implementing enemies with a billboarding system for a while:
For a new project I'm reusing some animated sprites from an old static camera shooter game I made. It consisted of shooting projectiles and hitting enemies advancing towards your position. The enemies were capsules which had an animated plane in front of them.
I wanted to go a step further and make a raycast system that would detect if the impact on a plane is on the alpha part of its texture. I achieved it using a SpriteRenderer and a plane that matched the size of the sprite which receives the impact of the Raycast.
The problem comes with the movement of the enemies. If I use Rigidbodies this conflicts with the plane which detects the impact, since I have to use a non-convex Mesh Collider for RaycastHit.textureCoord (With Convex colliders it doesn't return the correct position). I need Rigidbody based movement for the enemies to push each other when colliding.
I tried using Transform Movement, since the error does not occur, but this allows enemies to pass through each other and occupy the same space.
I started investigating navMesh but I'm not sure if it is possible to avoid collisions.
I started to place a group of trigger colliders on the enemy mimicking the shape of the sprite. But this makes it difficult for me to detect collisions when enemies do certain animations (Some enemies jump diagonally or their animations are a bit jittery).
I would like to keep the impact detection system for the sprite, but maybe there is another way to check the texture at the impact location.
I think my options are:
With rigidbody based movement: separate the animation and hit detection system from the enemy movement. And make the billboarding effect teleport to the object constantly.
With Transform movement: Detect if they are overlapping and move them in opposite direction to the overlapping to simulate the collision.
With motion based navMesh: I'm not sure if it will be useful to me, since the characters jump and I also believe that a Mesh Agent ship cannot simultaneously be an obstacle. I understand that the navMesh cannot be generated in runtime.
Leaving texture based detection and using the trigger colliders group: Animate the colliders to also follow the animations. Or simplify everything to a large collider, losing precision on impact.
-Find an alternative method to detect the impact coordinates in the texture, avoiding using RaycastHit.textureCoord and therefore Mesh Collider. (Although I would like to keep the impact detection system as it is, maybe there is a similar approach for the same result).
The reason I have not yet delved into these solutions is because I would like to keep the system simple. I'm trying to avoid separating the enemy into 2 gameobjects, simulating collisions or animating collider positions. I honestly don't know which way to go in order to move forward with the project.
So I've made this game right here: https://youtu.be/OxJEeOTldcM
And I'm facing an issue with the maze wall's colliders where, in certain levels (not just the one I'm showing in the video below), the ball goes through the walls when it's being forced against the wall by the movement.
Here you can see what I'm talking about: https://youtu.be/dVU3LWKuXJ0
I've already dealt with this and compromised by making the maze's rotation speed a lot slower than I initially intended to. I wanted the maze to rotate as fast as the player's movement, but that made the ball go through every single wall.
So the way I'm creating these levels is this: I have these pre-made PNG mazes, I import them into the level and I apply a Polygon Collider 2D on them. But it seems like that Polygon Collider alone can not properly deal with my game's collisions.
More than this, I started layering some empty game objects with box colliders on some of these walls, trying to make them stronger. This does work, but it's still not enough, and the ball keeps going through some of them.
The ball, as well as the walls, have rigidbodys on them, and I've set their Collision Detection to Continuous, based on some answers I've seen online regarding bad collision detection. Still doesn't fix it.
I've also tried making those maze's walls thicker in Photoshop, but I can't go thicker than they're right now without ruining the space the ball should be moving in, as well as distorting the maze's look.
There has to be a way in which I can fix this bad collisions of Unity. I need the ball to stop going through walls, as this is obviously an essential part of my game.
I also want to be able to set the maze's rotation back to being as fast as the player's movement, without having to limit its speed, but honestly I'd be happy if I can just fix this collision problem with the current speed.
The most frequent cause of "clipping through walls" is not bad collisions. It's usually due to poor understanding of Unity's separation of Physics and Frames.
Unity calculates collisions and physics on a fixed update cycle, and generates frames on a dynamic update cycle based on CPU resources. These are often explicitly leveraged by FixedUpdate() and Update() in Monobehaviours.
Everything in Unity happens on one of these 2 cycles. Frame based logic like changes to a transform happen on the dynamic update cycle, and physics logic like collisions happen on the fixed udpate cycle.
You are likely rotating your puzzle using the transform. This rotation to the transform happens outside of any physics calculation, and if you rotate fast enough you can end up clipping through walls before the physics calculation has a chance to run and generate a collision. This is very noticeable when you have very high FPS (like the uncapped FPS of the inspector). However, locking your FPS only masks the issue, and the bug can still occur.
To fix your issue, I implore you to make your rotation changes to the Rigidbody2D itself instead. Something like this should work:
public class SimpleRotation: MonoBehaviour
{
Rigidbody2D rigidBody2D;
void Start()
{
rigidBody2D = GetComponent<Rigidbody2D>();
}
void FixedUpdate()
{
if(rotateRight)
rigidBody2D.rotation += 1.0f;
if(rotateLeft)
rigidBody2D.rotation -= 1.0f;
}
}
Something else important to note is that Unity only updates input on the frame, so if you read your input during the FixedUpdate(), you may double read your input (or miss it completely). It is a good idea to read your input on the Update() cycle, and set a variable to transfer logic between the methods.
I have a nice trail renderer which moves steadly towards some other GameObjects and I need to know when the renderer "gets" to one of these GameObjects.
I've been looking around and it seems that, leaving aside the code controlling the collision itself, I need to:
1) Create a Collider (BoxCollider, for instance).
2) Attach to it a RigidBody, because moving the transform of the collider is not the best thing in terms of performance.
3) Apply a force to the RigidBody to make it move towards the objectives.
Overall, it seems like an overly complex setup to make if one object has just collided with another one, as I don't really it to do anything with physics (The ray won't bounce, nor come back, its all controlled by code).
Am I missing something or this is the only approach to this situation available on Unity?
I am making an FPS game using unity 3d, I've a problem in the shooting accuracy script. Can you tell me how I can change it with a single script that shoot the bullet and include the shooting accuracy and equipped to the gun, please?
If you are currently using a raycast, you should have no problem.
If you are spawning a sphere and thrusting it forwards, I suggest you use a raycast.
Raycasts go in a completely straight line. Bullets follow gravity, and quickly fall to the ground.
You don't see bullets, they move too fast. Raycasts are invisible.
When it hits something, it sends you back the information you need. If you make the sphere go too fast, it might glitch through objects.
You can learn about raycasts here.