ROBLOX How To's
Introduction
This page is for people who want to learn how to do some serious building and scripting. This also carries some information too small to be documented on the wiki.
Building
This is where all the major building topics are going to be stored.
Welds
No, not the kind where you take the weld tool and put two bricks together. This is serious welding, used for multi-handled weapons (such as stravant's NXT Gen Weapons), and much, much more. Now, here's a bit on welds:
Prerequisite: Know how to use a basic cframe (CFrame.new(#, #, #)), and how to index and change the properties of an object, using a script.
Part I : Welds.
What are welds? They are an object, that hold their parent part, and another part, in a position relative to each other. For example, hold one part 2 units to the right of the other brick. They can be used in places where parts need to be held together at odd angles, but still be able to move, such as for a vehicle.
Basic structure: The basic structure of a weld is as follows: The weld object is placed inside of a part, and a property is set to determine another part which should be welded to the original part. Then two CFrames, the C0 and the C1, tell the weld how the parts should be placed.
Part0: This property of a weld is an Object, it must always be set to the part the weld is in for the weld to work
Part1: This property of a weld is an object and tells is which part it should be attaching it's parent to
C0: the C0 of a weld, determines how the [offset point] should be attached to the Part0
C1: the C1 of a weld, determines how the Part1 should be attached to the [offest point]
Setting the values: Figuring out what to set the C0 and C1 to is a bit finicky, but one you get good at it, it can go quite quickly. For Welds, you dont have to worry about the C1, it's automaticaly set to a "unit" or unrotated CFrame, you only have to deal with C1 when working with motors, so ignore it for now. The C0 will tell the weld how it should attatch itself to the other part, eg.
[weld].C0 = CFrame.new(0, 2, 0)
This tells the weld that it should hold the part1 in a position 2 studs above the part0.
Rotating the CFrame: Now it gets a bit tricky. To rotate the CFrame you must use the following command, which is case sensitive. CFrame.fromEulerAnglesXYZ(#, #, #)
which is used in the following way... [weld].C0 = CFrame.new(0, 2, 0)*CFrame.fromEulerAnglesXYZ(0, math.pi, 0)
this tells the weld to attach the part1, two studs above the part0 AND rotate the part1 by 180 degrees relative to the part0
math.pi? Yes you use math.pi, as the number to rotate by, use it in the following fashion :
- math.pi = 1/2 of a turn
- math.pi/2 = 1/4 of a turn
- math.pi/4 = 1/8 of a turn
etc..
Putting it all together : Well, not that you know how to use the basics of a weld, here's how you put it all together. Here's an exapmle, which if you understood all the previous stuff should be enough for you to get it =P
Let's say that this is in a script, in a vehicle:
pln = script.Parent
local w = Instance.new("Weld")
w.Parent = pln.Engine
w.Part0 = pln.Engine --> part0 has to be the parent
w.Part1 = pln.Wing1
w.C0 = CFrame.new(0, 0, 6)*CFrame.new(0, -math.pi/5, 0)
Scripting
This is where all the major scripting topics are going to be stored.
Global Functions
Have you ever wondered how functions like wait() always work, even though you've never indexed them?
You can, with _G.
Script 1:
_G.Player = Workspace.Player
Script 2:
_G.Player:Destroy()
If you are familiar with pure Lua, you should notice that we have to index _G before the variable name. Scripts will error without it, because of security vulnerabilities.
You can used shared instead of _G, if you want.
Custom Objects
A custom object is something that you create that has properties like the other ROBLOX objects, such as game.Workspace.Brick.Transparency
Here's how:
your data type here will be a "Vector2"
Vector2 = {} --this decalres and object of the class "Vector2"(yes, it is a table as well)
function Vector2:new(one, two) --the function that we will use to create new objects of this class
newTB = {x, y} --this makes our new object with the properties, which you set as objects in the table
newTB.x = one --set the value to the one called in the argument
newTB.y = two
return newTB
end
--now we can call a new object of the class as such:
a = Vector2.new(7, 8)
print(a.x) --> 7
print(a.y) --> 8
a.x = 10
print(a.x) --> 10
How can you add member (methods, deemed properly) functions to your object though?
function Vector2:new(one, two)
newTB = {x, y}
newTB.x = one
newTB.y = two
function newTB.reset()
newTB.x = 0
newTB.y = 0
end
return newTB
end
a = Vector2.new(5, 8)
print(a.x) --> 5
print(a.y) --> 8
a:reset()
print(a.x) --> 0
print(a.y) --> 0
Changing The Camera's View
There are many more properties than just "CameraSubject" in a Camera object. You can use one of two things to change the camera's view:
1) [camera].Focus = CFrame.new(?)
2) [camera].Coordinateframe = CFrame.new(?)
Now you can finally make the ever elusive: cut scenes!
Terrain Generation
First, the way the terrain looks is based off of a number of points, either set randomly or by the user. The terrain genarator will try to drag the land upwards or downwards based on the height and position of these points, which I will refer to as "nodes".
When generating the terrain, the terrain generator will go through every part, in the list of parts being worked with, and do the following routine for it...
{ for each of the nodes do the following... 1) check the distance from the node to the current part.
2) make a modifier, based on the distance, such as the modifier being the distance/10.
3) then if the part is below the node, subtract the modifier from it's vertical size, or if it's above add to it. }
The farther away the point is from the nodes(s), the less it will be changed, resulting in a perfectly sloped surface.
But, this is just a simplified version, making the landscape's slope curved is a bit more tricky.
giving you a hint it might be something like this...
d = The distance between the node and the part being modifed m = the amount the part will be modified by
m = d^(10/d)
This probably won't make a very nice thing though, it will curve to sharply, getting it just right is quite finicky.
