Cursor modes are a type of game mechanic in Terraria. Auto Select and Smart Cursor are the two cursor modes implemented to make using tools and placing objects more convenient.
Auto Select[]
Auto Select will automatically select an item to use, depending on where the cursor is pointed. The item does not need to be in the hot bar. By default, Auto Select is activated by pressing Shift on PC, R3 on PS3/PS4, or pressing down the right thumbstick on Xbox 360/Xbox 1.
| Target | Item Selected |
|---|---|
| Blocks and most Furniture | Pickaxe |
| Tree, Giant Glowing Mushroom, or Cactus | Axe |
| Altar, Shadow Orb or Crimson Heart | Hammer |
| Extractinator | Silt or Slush |
| Cannon | Cannonball |
| Bunny Cannon | Explosive Bunny |
| When you point at an empty space or a wall, a light source will be selected based on the following criteria | |
| Cursor is far from the player | Glowstick, Spelunker Glowstick or Flare Gun |
| Player and cursor are in water (or other liquid) | Cursed Torch, Ichor Torch, Glowstick or Flare Gun |
| Player in water but cursor is not | Cursed Torch or Ichor Torch |
| If none of the above apply | Any torch |
A Flare Gun without Flares will not be selected. Nor will other light sources such as candles. If more than one item is equally appropriate it will normally select the first one in your inventory. And if the preferred item is unavailable it will usually fall back to something else.
Smart Cursor[]
Smart Cursor selects a target based on the active item. By default, it is toggled on and off by pressing Ctrl, or by holding down and dragging the right thumbstick. There is also an option in General Settings to make it last only while the key is held down. Smart Cursor mode is indicated by a slightly wider cursor, and the tile targeted is shown with a yellow box. On the Nintendo 
version, Smart Cursor is on by default unless the D-Pad or Touch Screen is used to target an area.
| Active Item | Behavior |
|---|---|
| Pickaxe | Digs a passage wide enough to pass through in the direction indicated be the cursor. A tunnel going diagonally upwards will often have to be widened to go back down.
As of 1.3 a vertical tunnel will have a width of 2 tiles, this is reduced from 3 tiles in previous versions. |
| Axe | Chops the base of the tree nearest the cursor. It will target branches when the base is out of range. An item that functions like an axe/pickaxe will target trees first then blocks. This can be easily seen with the Laser Drill (1.3+). |
| Hammer | Removes the wall nearest the cursor. |
| Block | Places a block at the nearest legal space to the cursor. If the space under the cursor already contains a block or other object, it will do nothing. However if the cursor is over an NPC or player, it will encase them in multiple layers. This is currently the only way to automatically fill a large area with blocks. On the Mobile version, this is quite unreliable.
|
| Wall | Places a wall at the nearest legal space to the cursor. Unlike other items, walls will only be placed by Smart Cursor within line of sight of the player. This makes it easy to fill a room without the walls "spilling" out. |
| Platform | Adds to existing platforms (in any direction, including vertical). |
| Minecart Track | Extends existing tracks horizontally or diagonally. |
| Wrench | Extends existing wires of the same color. |
| Wire Cutter | Removes the wire nearest the cursor. |
| Acorn | Places an acorn on top of grass if two blocks beside it are free. Accounts for optimal range, so that saplings have at least three empty tiles between them. |
| Paint Roller | Using the Paint Roller on one spot (holding it without moving the cursor) will make the cursor grow in a circle from the nearest wall tile, painting every wall including ones behind furniture and platforms but ignoring walls that are behind solid blocks. |
Using Smart Cursor with a multi-function tool, like Drax or a Hamaxe, may have unexpected results. These tools will behave as an axe by default, meaning they always target a tree if one is in range.
Smart Cursor can backfire unexpectedly, especially if the player has not realized it is active. For example, when extending platforms, if the player's aim is off, platforms can be built off in unexpected directions. Use of the "Ruler" functionality (always available as of 1.4) can help with this. Similarly, when digging near lava (or other liquids), the Smart Cursor can blindly mine blocks supporting the liquid.
Smart Cursor can be re-enabled to be used for common blocks (as in 1.2) by editing Terraria's config.json file manually. See config.json to know how to do it.
History[]
- Desktop 1.4.4.1: Fixed Paint Scraper not working with Smart Cursor when removing coatings.
- Desktop 1.3.0.1: Added Auto Select.