Unity 3D Environment Creation

Environments

• In 3D environments, Unity's Terrain generator helps in creating adjacent terrain tiles, sculpting and painting terrain, and adding trees and details.
• The term "terrain" refers to any section of land that simulates a world's external landscape, such as mountains, plains, and swamps.
• Some items may need to be modeled separately.

2D Environments

• In 2D environments, sprites are used, which are simple flat images not affected by directional light or skybox.
• Camera type is usually orthographic, making objects appear the same size and shape regardless of distance.
• A sorting layer is used to determine which sprites draw in front of each other.
• Sprites can be used in 3D scenes by setting the camera to Orthographic and image texture type as sprite.
• A sprite can have multiple images laid out in a grid called a sprite sheet.

Tilemaps

• A tilemap is a "map" of tiles that sit on a grid object, defining tile sizes and spacing.
• Tiles are individual sprite elements used to draw the game world.
• Selected tiles are placed on a palette, which is then used to draw the tiles onto the tilemap.
• To prepare sprites for use as tiles, ensure the Pixels per Unit property is configured to match the Cell Size property of the grid, and slice up sprites to minimize extra space.

Physics & Collision

• Collision occurs when the border of one object comes into contact with another object.
• Objects need a Rigidbody component to respond to gravity and a Collider component to detect collisions.
• A Rigidbody is the main component that allows an object to respond to gravity.
• A Collider is a perimeter that detects when other objects enter it.
• Colliders can be dynamic with a Rigidbody or static without a Rigidbody.
• Dynamic colliders can be basic primitive shapes or advanced mesh colliders for complex objects.
• Tilemap Collider 2D component handles collision for 2D tiles.

Physics & Collision (continued)

• You can attach a physics material to specify friction coefficient and bounciness.
• If Is Trigger is enabled, the object does not behave as a solid object and will simply allow other colliders to pass through.
• If Is Kinematic is enabled, forces, collisions, or joints will not affect the Rigidbody.
• Dynamic collider movements can be restricted partially by freezing axis using Rigidbody constraints or moving it lower in the Hierarchy.

UI

• The Render Mode property is used to determine how UI elements are rendered.
• Screen Space - Overlay is the default and most common render mode, where elements are static and stay on top of the screen.
• Screen Space - Camera render mode is affected by a selected camera and lighting.
• World Space render mode treats UI elements as game objects.
• You can update text in scripts as any other component.
• Empty objects can be used to group elements together, and layouts (vertical, horizontal, and Grid) can be used for better organization.

Animation

• Animations are premade sets of visual motions.
• Animations can be used in scenes, menu UI elements, navigations, and more.
• The focus is on character animation and cutscenes, which involve more than simple scripts and navigation.

2D & 3D Animation

• In 2D games, animations involve sequential images (sprites) that can be flipped through quickly to give the appearance of movement.
• In 3D games, animations use models to represent game entities and a skeleton (rig) to move the parts of the model.

Animation Features (Mecanim)

• Animation and Animator system (Mecanim) features include easy workflow and setup of animations, support for imported animation clips, and humaniod animation retargeting.
• It also includes preview of animation clips, transitions, and interactions, and management of complex interactions between animations with parameters and a visual programming tool.

Timeline

• Timeline System is similar to Animator System animations but with multiple independent objects synchronized.
• Every duration in the timeline is contained in a track, and Unity has several tracks by default, including activation track and animation track.
• Animation track leads to Animator System and overrides any old movement in the same duration.
• Common usage examples include switching between different objects, smoothing animation between tracks, and making cutscenes.

Animation Scripting

• Animation usually involves scripts.
• For Animator system, each animation needs at least one param to be defined first, then called from script after finding the animation component.
• For Timeline system, you need to add UnityEngine.Playables and use PlayableDirector to play and stop timelines.