Collider

Welcome back Developers, today we are gone learn about collider.

As per the unity manual the definition for collider is:
Collider components define the shape of an object for the purposes of physical collisions. A collider, which is invisible, need not be the exact same shape as the object’s mesh

and in fact, a rough approximation is often more efficient and indistinguishable in gameplay.

In simple word a collider gives your gameobject a physical nature so it can be a hard surface and other gameobject can’t pass through it.

Unity supports multiple colliders 3D as well as 2D.

    

Ok, we have this many collider but what to do with them how to use them in Scripts?  

Simple Unity provides some build-in method to use collider. They are:

Addition to this collider has some additional properties and methods which we cover later. But if you want to check them out go to the official unity scripting API link:https://docs.unity3d.com/ScriptReference/Collider.html

Let’s get to fun part now Codiiiiiing!!!!!!

Step1: Setup a 3D project name it as per your want’s.

Step2: Create a cube and a sphere 3D gameobject.

You will notice both gameobject already have a collider attach to them.

But if you import your custom Mesh from Modelling software (Max or Maya or Blender) you have to attach the colliders according to your shape.

Quick tip: In unity you can either select your imported model and attach a mesh collider to it and the collider will automatically take shape of your model. But believe me this method creates to many vertexes if a model is large and complex in shape so the better approach is to make a custom collider group using basic shapes collider (box, cylinder, sphere, etc).

Step3: Add a rigidbody to your any one collider gameobject. Adding rigidbody to any one collider is necessary otherwise the collision want work.

Don’t know why it is like that but it is what it is.

Step 4: Set Up scene.

Move your sphere collider above your cube collider.

Stretch the cube collider a little bit, add rigidbody to sphere and save scene hit play.

As you can notice sphere hit the ground, so They are colliding but what to do with it.

Step5: Create a script and add it to sphere gameobject.

Wow we have a bouncing ball. Great!!

Using OnCollisionEnter method you can detect whether the script attached to game object as hit anything if it does the code block execute.

Plus, if you have noticed OnCollisionEnter(Collision collision) takes a parameter.This parameter tells us about that which object our sphere has hit with so we can manipulate the other collided object as well.

Let me show you how.

(Note OnCollisionEnter runs only once- when the two object collides.)

Wow!! Now oursphere bounce and cube rotate. Great.

OnCollisionExit(Collision collision) :Runs only once after the collision is ended.

OnCollisionStay(Collision collision) : Runs multiple times till the two objects are collided.

This Blog is Open to edits and feedback.

Until Than Happy Codiiing!!!