As far as the player experience goes, placed items fall into several "layers" laid over the map, with a little overlap; the most obvious distinction is that the first layer represents "foreground" objects that can block the player's movement, while the others represent various "background" layers, with little or no effect on the player's passage.
- Placed foreground objects: A foreground object is something that collides with the character and inhibits movement. The vast majority of these are blocks, and in turn nearly all blocks are placed in the foreground layer. There are a few non-blocks in the foreground layer, such as Boulders and Teleporters, and a few objects (e.g. Doors, platforms) that can interact with both this and the next layer. Thorny bushes and their variants are among the few plants in the foreground, but Living Trees are also made of foreground blocks.
- A background object is something that doesn't collide with characters, but cannot share a tile with a foreground block. (This is sometimes called the "furniture layer".) Characters can move through them freely. These include the majority of plants (trees, vines, tall grass, etc), and almost all furniture. Many background objects are for visual appeal only, though several, such as crafting stations and storage items, have functions for the player.
- Some objects possess qualities of both the foreground and furniture. Doors are foreground objects when closed and background ones when open. Some furniture (especially Platforms) are mainly background objects, but a character can stand on top of them. (Pressing the ▼ 下 key causes the character to "jump down" by falling through.) Aside from platforms, many of the "flat surface" furniture items act like this: Workbenches, Tables, and the like. Bubble blocks act like solid blocks with respect to liquids, but otherwise as furniture items.
- Liquids occupy their own layer: While they normally flow around blocks and can't be placed in them, blocks can be placed in liquids (except lava) and the liquid is then trapped but not destroyed. A few furniture objects can similarly trap liquids (chests), but normally liquids can flow through background objects, perhaps breaking them in passage. Liquids will slow the passage of characters and most projectiles. With appropriate accessories or buffs, players can walk on the surface of a liquid as if it were a platform. Liquids can partly or completely hide furniture-layer items they cover, as well as characters or enemies within them.
- Walls do not impede objects on any other layer, but they can provide "support" for placing foreground or background objects. Otherwise they do not interact with other layers, and are depicted behind everything except the biome-dependent "scenery" images. Natural walls can affect biome determination and enemy spawning, and in some cases they can participate in biome spreading.
- The "wiring layer" contains wire and actuators; these can overlap and interact with foreground or background objects, and never collide with the character or other entities. They are not visible unless the player is either wielding a mechanism-related object, or else using a Mechanical Lens or The Grand Design. When such wiring objects are visible, they are not concealed by objects on any other layer. Note that most other mechanisms are either foreground objects or background furniture.
- 如果自动暂停处于关闭状态且你的物品栏处于打开状态，从物品栏中拿起物品并在你要放置此物品的地方按⚒ 使用/攻击键。
- 无论是否开启了自动暂停，如果一件物品处于物品栏的热键栏中，就像选择武器或工具那样选择它，然后在你要放置此物品的地方按⚒ 使用/攻击键。
To free an item and pick it up again, you normally use a Pickaxe. As a special case, natural trees (including cactus and giant mushrooms) require use of an axe to harvest them. Note that anything requiring an axe to harvest cannot be directly placed by the player.
- 放置区域必须适合指定物品。物块可以放置在和任意其他物块相邻的空白空间中，家具物品却通常会有更加严格的放置要求。大多数需要有坚固、平坦的表面，但有些要求更宽松（比如火把），或者会有更严苛（比如门或蜡烛）。在 18.104.22.168 更新以后，用"界面"选项中的“放置预览”选项可以更轻松地找到合适的放置区域。