How to make a brick spawn at a random location?

You can use math.random() to get around this. Basically you can generate a random x and z coordinate and keep a static y coordinate. If you do not want a part to be spawned 2 times in the same place you could use a table to store the previous vectors and check if the same vectors has been indexed or not. And alternatively if you do not want your part to collide with in-game models such as trees you could check if the place where you'd put your part is occupied by other objects. You could do this with region3. Here is a simple code I wrote which generates random parts:

 local cache = {}



while wait(0.1) do

local randomVector = Vector3.new(math.random(-255, 255), 0.5, math.random(-255, 255))

if cache[randomVector] then

repeat randomVector = Vector3.new(math.random(-255, 255), 0.5, math.random(-255, 255)) until not cache[randomVector]

local part = Instance.new("Part")

part.Parent = workspace

part.Position = randomVector

else

local part = Instance.new("Part")

part.Parent = workspace

part.Position = randomVector

end

end

It is not really good you can improve yours by adding different functionalities as I said above. You could convert your parts to a region3 and then use workspace:FindPartsInRegion3(region) to check if the place where you'd put your part would be occupied by other objects. You could use this function to make the job easier for you:

  local  function partToRegion(Part)  
       return Region3.new( Part.Position - ( Part.Size / 2), Part.Position + (              Part.Size / 2) ); 
   end