Sprite sheet with Unity

The goal here is to use sprite sheet with Unity.
The most common scenarios are:

• I already have a sprite sheets generated, how do I import the sprite sheet in Unity?
• I want to reduce de number of draws calls, should I use a spritesheet with Unity?

Import sprite sheets

Importing sprite sheet with Unity is simple, just drag and drop the sprite sheets in the resource folder.
If you need a sprite sheet you can test with this one : sonic-sprite-sheet.png

Next make sure the Sprite mode is set to Multiple :

Then you can open the Sprite Editor :

You can slice the sprites, normally you do not need to tchange the default options :

After the sprite sheet slicing, you can click on Apply to confirm the change or Revert.

After the slicing you should have :

In the resource folder you see the sprites :

Everything is done, you can now use the sprites in your game!

Reduce the number of draws calls: Sprite Atlas

If you want to reduce the number of draws calls but you have multiple sprites in your games, you can generate a sprite sheet with unity, those are call Sprite Atlas.

To create a Sprite Atlas you can do it in less than 1 minutes : Right click on you resource folder

Then you can add the sprite you want to pack in the Inspector:

You can render you Sprite Atlas with the button Pack Preview.
Unity should be able to use your Sprite Atlas you do not need to do anything else.