is it possible to check if an object exists at a specific vector

trying to make it so that players cant spawn items inside of another item. all the vectors will be on a grid so assume i know exactly what the vector the object should be at if it were there.

i hope this all makes sense

This is pretty straightforward with Physics.CheckSphere:

Vector3 spawnPos = (whatever position you want to check)
float radius = (whatever radius you want to check)

if (Physics.CheckSphere (spawnPos, radius)) {
    // found something
} else {
    // spot is empty, we can spawn
    Spawn();
}

You can use Layers to selectively cast against certain objects, just check the documentation. You might want to use Physics.OverlapSphere instead, if you need more information about the location you’re trying to spawn at.

There are lots of ways to approach this problem. Assuming the objects have colliders, you can check if an object exists within a specified sphere using. Physics.CheckSphere(). You can get a list of all object withing a specified sphere using Physics.OverlapSphere() (also requires a collider on the objects). You can tag all the possible game objects with a common tag and then use GameObject.FindObjectsWithTag() to find all the objects, then use Vector3.Distance() (or a simple ‘==’) to figure out if any of the objects are at that position. This method does not require a collider. You could create an array of boolean values that maps to the grid. Each time a game object is position on the grid, you could set the boolean value for that position to ‘true’. Check would just be a simple array lookup.