I have a pane with one cube on it with a spawner which will spawn cubes out when the game is played. The pane can be rotated and the cubes should stick to it and move forward.
The part i am stuck on is making the cubes that come from the spawner to stick.
I managed to make the original cube stick using
Object1.transform.parent = Object2.transform;
I also managed to make the spawner stick to the pane using the same method.
However when i use this the first cube will stick fine and the cubes from the spawner are not showing up. From what i have researched it could be a scaling issue. Also the spawned cubes do appear under the cube as "Cube(clone)" but their scale is diffrent to the original cube. I have also noticed the scale of the original Cube changes when i press play. It goes from - (10,10,10) to float numbers.
A solution i tried was to set the scale but when i done this the objects did not stick on to the pane at all.
However they did spawn normally.Using this method.
void Update () {
Vector3 scale = new Vector3(10, 10, 10);
Object1.transform.localScale = scale;
Object1.transform.parent = Object2.transform;
}
If anyone has any ideas it will be much appreciated.
In situations like this, it's quite often best to parent an object first, then deal with the local transformations. Local transformations such as transform.localPosition, transform.localRotation and transform.localScale deal with the object's local values in relation to the parent.
There's a paragraph at the end of this page that describes it well:
Note that the parent transform's world rotation and scale are applied
to the local position when calculating the world position. This means
that while 1 unit in Transform.position is always 1 unit, 1 unit in
Transform.localPosition will get scaled by the scale of all ancestors.
Related
I'm trying to make a pick up objects mechanic like the one in Amnesia. It's easy to calculate needed rigidbody's velocity, so that the held object stays in front of camera, but my problem is that the object doesn't rotate at all when I hold it. And I would rather have it always be rotated towards the camera. This could easily be achieved with simply parenting the object to player's camera, but...
The behaviour I'm after is as follows: if the bottle I picked up was standing on a table, with neck of the bottle facing ceiling, I would like to see this bottle always with its neck facing ceiling while I hold it. But if this bottle collides with something, it should behave like it actually bumped onto something, so it should rotate some small amount, but it should always try to return to its "original" rotation (in this case, neck facing ceiling).
I think that I need to calculate angular velocity for that and probably have some lerp to return to original rotation, but I'm at a loss on how to do that properly.
I think that the first thing I would need to do is to store the initial direction the moment player picks object up:
Vector3 targetDirection = playerCamera.transform.position - transform.position;
Script is on the held object, so "transform" refers to it. In FixedUpdate() I probably need to have some interpolation, so that angular velocity always tries to rotate the object to original rotation:
rigidbody.angularVelocity = Vector3.Lerp(rigidbody.angularVelocity, targetAngularVelocity, lerpSpeed * Time.fixedDeltaTime);
I don't know how to calculate targetAngularVelocity, because after all I would like the held object to return to original rotation smoothly. I'm not even sure if that's the right way to do this thing and perhaps I should do something else than to calculate angular velocity needed to rotate object properly. I tried just interpolating localRotation to original local rotation, but that did not allow the held object to bump on stuff (the movement then was very jittery). Any ideas?
You need a stabilizer. A script which will add torque/angular velocity to the object, whose angle is different from the target one. Say, you have two variables: targetDirection and currentDirection aka transform.forward. Then you write something like this in fixed update:
var rotation = Quaternion.FromToRotation(currentDirection, targetDirection).eulerAngles * sensitivity;
rigidbody.angularVelocity = rotation;
I recommend to set sensitivity about 0.05 and then increase it if the object stabilizes too slow.
Probably I confused the order, so you should put minus somewhere, but the approach itself is applicable.
I am building a 3d Billiard game in VR using Unity3d.
I try to display a miniature copy of the billiard "table" (actually a cube), like it is at any given moment.
I tried instantiating the root of the billiard hierarchy, just to find out it will instantiate the original gameObject (runnings its Start() methods) which totally makes sense, just not what i am trying to do.
In practice I have a billiard root, which has all the geometry of the table, and all balls as children, those balls can interact physically.
On button press I try to create a hologram of the table, with all its balls at their position at any given time.
So If a player hits a ball and it moves in the original, it should display the same in the miniature.
I thought it might be possible to translate the ball positions (and table rotation etc) every frame to the miniature. but that seams very un optimal.
var midPoint = (leftHand.transform.position + rightHand.transform.position) / 2;
var miniature = Instantiate(gameObject, midPoint, transform.rotation);
miniature.transform.localScale = new Vector3(0.1f, 0.1f, 0.1f);
this obviously does not work as i described above. It creates a completely new instance of the billiard cube. (this code was run from a script inside the billiard root)
The board itself probably doesn't move, so you can just make holograms and simulate the balls.
Since Unity 2018.2, you can create physics scenes and simulate them manually.
For that problem you would need to:
Stop physics simulations.
Physics.autoSimulation = false;
Create a new scene for independent physics simulation.
var physicsPreviewScene = SceneManager.CreateScene("Physics Preview Scene", sceneParams);
Copy the physics-relevant objects and components to the preview scene.
Many ways to do it, but basically colliders, rigidbodies, and for objects you need visuals for, renderers.
You can use caching to avoid creating these every time.
You can also, in theory, have the simulation on the main scene, but then you need to make kinematic all the stuff you don't want simulated, and there are some gotchas.
Then simulate manually.
Get the PhysicsScene from the preview scene: var physicsScene = physicsPreviewScene.GetPhysicsScene();
Simulate: physicsScene.Simulate();
So yea, short of avoiding the components unrelated to physics in the copies, you can't avoid the duplicates; only mitigate their impact with pooling and/or caching.
Another technique is to use casting (spherecasting, in this case) to make a mockup physics simulation, stepping multiple casts with velocity, acceleration (gravity for example) and Time.fixedDeltaTime, and reacting to intercepts/hits as collisions, with Vector3.Reflector something similar. But this will only give you an approximation of how physics would react, and is not going to be an actual (accurate) physics simulation like having multiple PhysicsScenes will.
I'm going through a few different Unity tutorials and the way a game object is moved around in each is a little different.
What are the pros/cons to each of these methods and which is preferred for a first person RPG?
// Here I use MovePosition function on the rigid body of this component
Rigidbody.MovePosition(m_Rigidbody.position + movement);
//Here I apply force to the rigid body and am able to choose force mode
Rigidbody.AddForce(15 * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
// Here I directly change a transforms position value, in this case the cam
Transform.transform.position = playerTransform.position + cameraOffset;
Thanks!!
EDIT;
Something I have noticed is that the applied force seems to memic wheeled vehicles while the position changes memic walking/running.
RigidBodies and Velocities/Physics
The only time, I personally have used the rigidbodys system was when implementing my own boids (flocking behaviour) as you need to calculate a few separate vectors and apply them all to the unit.
Rigidbody.MovePosition(m_Rigidbody.position + movement);
This calculates a movement vector towards a target for you using the physics system, so the object's velocity and movement can still be affected by drag, angular drag and so on.
This particular function is a wrapper around Rigidbody.AddForce I believe.
Pros :
Good if realistic physical reactions is something you are going for
Cons:
A bit unwieldy to use if all you are trying to achieve is moving a object from point A to point B.
Sometimes an errant setting set too high somewhere (for example: Mass > 10000000) can cause really screwy bugs in behaviour that can be quite a pain to pin down and mitigate.
Notes: Rigidbodies when colliding with another Rigidbody would bounce from each other depending on physics settings.
They are also affected by gravity. Basically they try to mimic real life objects but it can be sometimes difficult to tame the objects and make them do exactly what you want.
And Rigidbody.AddForce is basically the same as above except you calculate the vector yourself.
So for example to get a vector towards a target you would do
Vector3 target = target.position - myPosition;
Rigidbody.AddForce(target * 15 * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
If you don't plan on having any major physics mechanics in your game, I would suggest moving by interpolating the objects position.
As it is far easier to get things to behave how you want, unless of course you are going for physical realism!
Interpolating the units position
Pros :
Perhaps a little strange to understand at first but far simpler to make objects move how you want
Cons:
If you wanted realistic reactions to objects impacting you'd have to do a lot of the work yourself. But sometimes this is preferable to using a physics system then trying, as I've said earlier to tame it.
You would use the technique in say a Pokemon game, you don't stop in Pokemon and wait for ash to stop skidding or hit a wall and bounce uncontrollably backwards.
This particular function is setting the objects position like teleporting but you can also use this to move the character smoothly to a position. I suggest looking up 'tweens' for smoothly interpolating between variables.
//change the characters x by + 1 every tick,
Transform.transform.position.x += 1f;
Rigidbody.MovePosition(m_Rigidbody.position + movement);
From the docs:
If Rigidbody interpolation is enabled on the Rigidbody, calling Rigidbody.MovePosition results in a smooth transition between the two positions in any intermediate frames rendered. This should be used if you want to continuously move a rigidbody in each FixedUpdate.
https://docs.unity3d.com/ScriptReference/Rigidbody.MovePosition.html
Rigidbody.AddForce(15 * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
This will make the object accelerate, so it won't travel at a constant velocity (this is because of Newton's second law, Force=mass*acceleration). Also if you have another force going in the opposite direction this force could get cancelled out and the object won't move at all.
Transform.transform.position = playerTransform.position + cameraOffset;
This will teleport the object. No smooth transition, no interaction with any forces already in the game, just an instant change in position.
I have a finger object. It is just three cubes representing the finger parts.
The 2nd cube is the child of the 1st one. And the 3rd cube is the child of the 2nd one.
This is the heirarchy: Cube1 -> Cube2 -> Cube3
My goal is to apply a rotation angle to the first cube and let the other cubes do the same locally.
Example: Apply 30 degrees Z rotation to the first cube, 30 degrees Z rotation to the 2nd cube, and also the 3rd one.
This will make a finger that look like this:
(Forgive me if it doesn't look like a finger)
In every Update() frame, I will change the angle (it's just one number) and it will rotate every cube for me.
My question is:
How do I make all these cubes collide properly with other objects?
I tried putting the Rigidbody on all of them and set isKinematic=false because I want to transform them myself. But I still cannot use transform.rotation to update my rotation because it will miss the collision with a ball very easily (especially the tip of the finger because it moves faster than other parts). Continuous detection doesn't help.
So I tried using rigidbody.MoveRotation() and rigidbody.MovePosition() instead, which is a pain because they need absolute values. They worked but the animation is so jumpy when I change the angle quickly.
I'm guessing that the animation is jumpy because there are many Rigidbodies or because the physics engine cannot interpolate the position of each box properly when I use MoveRotation() and MovePosition().
I need to use MovePosition() also because when I use only child.MoveRotation(transform.parent.rotation * originalChildLocalRotation * Quaternion.Euler(0, 0, angle)), the position doesn't move relative to the parent. So I have to compute child.MovePosition(parent.TransformPoint(originalLocalPositionOfTheChild)) every frame too.
I've already tried depthmask shaders and examined some other ideas, but it seems like it doesn't suit me at all.
I'm making an AR game and I have a scene with a house and trees. All these objects are animated and do something like falling from the sky, but not all at once, but in sequence. For example, the house first, then trees, then fence etc.
(Plz, look at my picture for details) http://f2.s.qip.ru/bVqSAgcy.png
If user moves camera too far, he will see all these objects stucking in the air and waiting for their order to start falling, and it is not good. I want to hide this area from all sides (because in AR camera can move around freely) and make all parts visible only when each will start moving (falling down).
(One more screen) http://f3.s.qip.ru/bVqSAgcz.png
I thought about animation events, but there are too many objects (bricks, for example) and I can't handle all of them manually.
I look forward to your great advice ;)
P.S. Sorry for my bad english.
You can disable their(the objects that are gonna fall) mesh renderers and re active them when they are ready to fall.
See here for more details about mesh renderer.
Deactivate your Object. You might use the camera viewport coordinates to get a y position outside the viewport. They start on the bottom left of the screen (0,0) and go to the top right of the screen (1,1). Convert them to worldspace coordinates. Camera.ViewportToWorldPoint
Vector3 outsideCamera = Camera.main.ViewportToWorldPoint(new Vector3(0.5f, 1.2f, 10.0f));
Now you can use the intended x and z positions of your object. Activate it when you want to drop it.
myObject.transform.position = new Vector3(myObject.transform.position.x, outsideCamera.y, myObject.transform.position.z);
Another thing you could additionally do is scaling the object from very small to its intended size when it is falling. This would prevent the object being visible before falling when the users point the camera upwards.
1- Maybe you can use the Camera far clipping plane property.
Or you can even use 2 Cameras if you need to display let's say the landscape on one (which will not render the house + trees + ...) with a "big" far clipping plane and use a second one with Depth only clear flags rendering only the items (this one can have a smaller far clipping plane from what I understand).
2- Other suggestion I'd give you is adding the scale to your animation:
set the scale to 0 on the beginning of animation
wait for the item to be needed to fall down
set the scale to 1 (with a transition if needed)
make the item fall down
EDIT: the workaround you found is quite just fine too! But tracking only world position should be enough I think (saving a tiny amount of memory).
Hope this helps,
Finally, the solution I chose. I've added this script to each object in composition. It stores object's position (in my case both world and local) at Start() and listening if it changes in Update(). So, if true, stop monitoring and set MeshRenderer in on state.
[RequireComponent(typeof(MeshRenderer))]
public class RenderScript : MonoBehaviour
{
private MeshRenderer mr;
private bool monitoring = true;
private Vector3 posLocal;
private Vector3 posWorld;
// Use this for initialization
void Start()
{
mr = GetComponent<MeshRenderer>();
mr.enabled = false;
posLocal = transform.localPosition;
posWorld = transform.position;
}
// Update is called once per frame
void Update()
{
if (monitoring)
{
if (transform.localPosition != posLocal || transform.position != posWorld)
{
monitoring = false;
mr.enabled = true;
}
}
}
}
Even my funny cheap сhinese smartphone is alive after this, so, I guess, it's OK.