This is a paid asset, but now you can download Grid Placement System for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Grid Placement System v1.4.0
Grid Placement System allows players to easily place items onto a grid at runtime. Perfect for city builders, tower defense and all sorts of other genres where players need to place items.
Grid Placement System is designed to be extremely customizable and with ease of use at its core.
No object configuration needed. Pass an object to the grid and it just works! When the grid manager is passed an object to be placed into the grid it handles all of the calculations to determine how many grid cells it takes up.
Customize all aspects of the grid. Settings include width and height, amount of cells, visualization of grid cells, visualization of occupied cells, the object’s alignment within its cell(s), the visual feedback when placing an item and more!
Don’t like square grid cells? You can change the sprite to show any shape you like, a circle, a triangle, a dot?
Easy to use. The grid settings provide one place to customize everything to do with the grid.
Custom editor tools. Visualize the modifications you make to the grid settings in real-time without entering play mode.
Suitable for a wide range of genres. Examples include: tower defense, city builders, simulation, and anything where the player is required to place an item onto a grid.
The showcase images use 3D models from a 3rd party low poly asset pack. These models are not included in this package.
You can view the documentation here: Documentation
Features:
Customize grid width and height
Customize grid cell size
Customize the visuals of all aspects of the grid.
Move objects in the grid with user input. Mouse or Touch controls. You can define your own input definitions for the grid.
Grid Snapping.
Rotation Handling.
Object alignment. How is the object centered within its cell(s)
Remove objects from the grid.
Delete objects from the grid.
Cancel object placement
Paint Mode Allows for continuous placement of objects.
Detects invalid placements. Either overlapping objects or if objects are partially outside the grid.
Add to the grid programmatically. You don’t have to place an item by moving it into the desired position. You can pass in the exact cell position and alignment you want instead.
Saving & Loading functionality. The grid manager provides methods/properties to enable you to retrieve all the grid data for placed objects. Along with populating the grid with a list of grid data. This allows you to load the grid into a previous state.
Mobile Support. You can configure the input type of various runtime platforms within Unity.
Customize Grid Input. Create custom input definitions to allow users to interact with the grid in any way they like.
Position Offset. Override the snap position to allow the objects to hover.
Custom Validation. Adds additional control over marking an object as invalid.
Custom Sizing. Easily set the size of the object.
Move the Grid at Runtime. Move the grid and all objects parented to the grid.
Rotate the Grid at Runtime. Rotate the grid and all objects parented to the grid.
Supports 100,000,000 grid cells.
Find Nearby Objects
11 Demo Scenes.
Add Progamatically Demo – Setup and place numerous objects into the grid all through code.
Basic Grid Demo – Shows a simple example of how you could implement the grid. Also contains examples for saving and loading the grid data.
Large Grid Demo – Shows how large grids can be created and managed.
Multiple Grid Demo – Shows how to interact with more than one grid at once.
Paint Mode Demo – Shows how to use the grid’s paint mode functionality.
Custom Position Offset Demo – Shows how to add a custom position offset to objects being placed.
Custom Validation Demo – Shows how to apply custom validation to a grid object.
Move Grid Demo – Shows how to move and rotate the grid at runtime.
Custom Placement Demo – Shows various methods to set the initial position of an object being placed.
Object Sizing Demo – Shows how to add a custom bounds component. Also shows how to set the grid height position.
Find Nearby Objects Demo – Shows how to search for objects surrounding a grid object.
The grid placement system works with both Unity’s new Input System and the Legacy Input Manager. This is because you create the input definitions for the grid system. This allows you to define how the players interact with the grid. The documentation covers this in more detail and the sample scenes provide examples of the input definitions.