of effecting the appearance of a game object

這種材質不會影響物件外觀 但會影響物理引擎運算

they effect the way that the object reacts

想想看籃球與保齡球之間的差異

to the physics engine. Consider the difference

除了兩者彈跳的方式、重量的差異性

between how a basketball and a bowling ball

表面質感的差異 與其它表面產生的反應也有差異

might bounce. Whilst there is a difference

物理材質可點選專案裡的Create鈕來建立

in their mass, their surfaces are also

從檢視裡調整和其它表面互動的設定

very different and they react to other

利用摩擦力的設定來控制互動的結果

surfaces very differently. Physic materials

動態摩擦(Dynamic Friction) 用來設定物件移動產生的摩擦力

can be created from the Create button

靜態摩擦(Static Friction)用來設定 從靜止狀態移動一個物件需要多少力量

on the project panel.

彈力(Bounciness)設定物件的彈力大小

And they're edited in the inspector to

綜合摩擦(Friction Combine) 設定物件對其它物件材質的反應

control how the surface reacts to another

摩擦方向(Friction Direction) 設定各軸向的摩擦力

surface. They do this by controlling friction.

而動態摩擦 2和靜態摩擦 2 是用來控制摩擦方向的三個軸向數值

Dynamic Friction is how much friction

在這個範例裡 我們將方體和工作臺加入了物理材質

exists whilst the object is moving

物理材質可在物件碰撞體屬性裡指定

and Static Friction is how much

你可以在碰撞體元件裡 看到一個指定物理材質(Materia)的設定

force is required in order to move the

當開始播放遊戲時 方體物件顯得滑溜又略有彈力

object from a static position.

那是因為我的動態摩擦和靜態摩擦設定為 0

Bounciness does exactly what it sounds like.

代表平滑表面上沒東西阻止的了它 同時也帶了些許彈力

It controls how bouncy the object is.

如果我將彈力設定提高它就會彈離工作臺

And the Friction Combine settings control

如果我想限制它在X軸的摩擦力

how they respond to another object

我可以在物理材質檢視裡

with a certain material. Friction Direction

將摩擦方向的X軸設定為1 並加大動態摩擦2的數值

will allow you to control friction

接著我將彈力降低 這樣它就不會彈離工作臺

in a particular axis and the dynamic

你可以看到方體物件滑動了一下就停止 這是因為摩擦方向限制的關係

and static friction 2 properties

所以我們將限制在調低一點 你可以看到它開始滑動

will give you control over those three axes.

這樣你就能了解

In this example we've applied this

物理材質可以完全控制物件表面的設定

particular physic material to our power cube

以及物件和其他物件的碰撞行為

and our work bench.

The physic material is applied to the

collider in any given game object

and you can see that there's a slot for

material within the collider settings.

You can see that if I press play,

it bounces slightly and is also very slippery.

This is because I've used 0 for dynamic

and static friction, meaning there's nothing

stopping it from slipping around and

I've also made it slightly bouncy.

If I make it very bouncy

then it's going to bounce off of the table.

And for example if I wanted to restrict

it's movement in a particular axis

so I can see that the X axis is the direction

in which it's sliding, so what I could do

is go back to that material and I'll set

my friction direction of X to 1 and

increase the dynamic friction. I'm going to turn

bounciness back down to a lower number

so that it doesn't bounce off the table.

And you can see that it's slowing to a halt

because of the amount of friction involved there.

So we could make that slightly lower

and you can see it begins to slide.

So hopefully you can see that with

physic materials you can completely control

the surface of an object

and how it responds to others.