Random terrain

Introduction

Procedurally generated terrain, often refered to as randomly generated terrain, is a terrain that is created via script rather than by hand. This creates the ability to have games that are a completely different experience every time as well as use alot less work.

The most basic form

The most basic algorithm, or steps used to solve a certain problem, is to place bricks of random size in random positions across your baseplate. To do this we will set up a simple for loop that instances a new, anchored part every time.

for i=1,200 do
    local a=Instance.new("Part",workspace)--creates new part in workspace
    a.Anchored=true

Next we will set the size to a random amount. For this we will use the function math.random()

    a.Size=Vector3.new(math.random(1,20),math.random(1,20),math.random(1,20))

This will set the Size to a random amount be 1 and 20 for the X,Y and Z size. Now for the last step of our algorithm, use CFrame to place the brick in a random spot. We will easily just place the X and Z axis using math.random() yet for the Y axis, we'll have to do something special. Being that we want all the bricks to stay on the ground, we want their base to be at 0. Now being that the Position of a brick in roblox uses the center of the brick, we'll have to divide the Y size in half, so that it sits just perfectly on 0. So it would be :

    a.CFrame=CFrame.new(math.random(-100,100),a.Size.Y/2,math.random(-100,100))
end -- for the for loop

Heightmap

A heightmap shows different elevations across the whole map. For making a basic one, we will just have a script in the base of our map. This way we can specify the size of the map we want and where it will be positioned easily. To start, we will define three variables.

Xlength=10
Zlength=10
par=script.Parent

Xlength and Zlength will be the dimensions ( in parts ) that will be used whereas par shows the base, which is what this is all based off of. Now, how we will create all the bricks is similar to last time only now it will use two for loops.

for x=1,Xlength do
for z=1,Zlength do
    local a=Instance.new("Part",workspace)
    a.Anchored=true

By setting it up this way, it'll start from a corner and go all the way to the edge, then go back to that corner and do the same thing just one up until the map is complete. Now the sizing of the brick will be a little bit more unique than last time. Now we will only use math.random() on the Y axis, the other two we will divide the par.Size by their equivalent Xlength or Zlength. This will insure that it will sit perfectly inside our base, but only if the formFactor is set to Custom

    a.formFactor="Custom"
    a.Size=Vector3.new(par.Size.X/Xlength,math.random(1,20),par.Size.Z/Zlength)

Now we will do the tricky part, positioning it with CFrame. There are 3 basic steps to getting the CFrame perfect. Step 1 will be very similar to the first example. The Y axis will be done exactly the same way, however the other 2 axis are going to have to be done by doing the size.X*x and size.Z*z

    a.CFrame=CFrame.new(x*a.Size.X,a.Size.Y/2,z*a.Size.Z)

This is done because now it'll take the for loop x and z values, and multiply them by the size to get it to scale. Next we're gonna add the position of the part, and also subtract half of the size on the X and the Z.

    a.CFrame=a.CFrame+Vector3.new((par.Position.X-par.Size.X/2),par.Position.Y,(par.Position.Z-par.Size.Z/2))

The reason we also subtract half of the X and half of the Z is because then it will make it offset from the corner, instead of the middle of the brick. Now if you run it like this, you'll notice that it still comes off the base a little bit. This is because the bricks aren't being moved by the corner as well, but by the middle of them. We will fix this in the third and final step, subtracting half of the x and z size of the brick being placed.

    a.CFrame=a.CFrame-Vector3.new(a.Size.X/2,0,a.Size.Z/2);
end end -- an end for each for loop