Inside Magnitude

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#1

How do I can get the inside magnitude by direction in part? I tried use:

local distance = direction * Part.Size * direction

but it doesn’t work correctly
I need like this:

1 Like
#2

Hello there!

You want to do it in a 2D plane? If not you can use raycasting:

local Result = workspace:Raycast.new(bla bla bla)

local Distance = Result.Distance

If you want it in a 2D plane maybe you can do it using trigonometry

a (Distance) = b^2 ((Part side / 2) ^2) + c^2 (Distance from the center to the colision point^2)

The following code might not work, i’m not too good at math

local X = Direction.X
local Y = Direction.Y

if X == 1 or X == - 1 then

local Distance = math.Sqrt(Part.Size.X^2 + (Part.Size.Y * (Y * math.sigh(Y))^2))

else

local Distance = math.Sqrt(Part.Size.Y^2 + (Part.Size.X * (X * math.sigh(X))^2))

end

Hope it helps ;]

#3

How general a solution are you looking for? Do you literally just need the 2D distance from the center of a perfect square to the nearest side for any direction in the plane, or is what you really the distance from any point inside an arbitrary 3D object to the surface, in the some provided direction?

In the worst cases, where the “part” is non-convex or non-manifold mesh, this problem can get pretty difficult.

#4

Thank you for your reply, but I want to do this in 3D and not use the Raycasting

#6

this should work

local function getClosestSurfacePoint(part, point)
    local halfSize = part.Size * 0.5
    local localPoint = part.CFrame:PointToObjectSpace(point)

    local clampedPoint = Vector3.new(
        math.clamp(localPoint.X, -halfSize.X, halfSize.X),
        math.clamp(localPoint.Y, -halfSize.Y, halfSize.Y),
        math.clamp(localPoint.Z, -halfSize.Z, halfSize.Z)
    )

    if localPoint.X ~= clampedPoint.X then
        clampedPoint = Vector3.new(halfSize.X * math.sign(localPoint.X), clampedPoint.Y, clampedPoint.Z)
    elseif localPoint.Y ~= clampedPoint.Y then
        clampedPoint = Vector3.new(clampedPoint.X, halfSize.Y * math.sign(localPoint.Y), clampedPoint.Z)
    elseif localPoint.Z ~= clampedPoint.Z then
        clampedPoint = Vector3.new(clampedPoint.X, clampedPoint.Y, halfSize.Z * math.sign(localPoint.Z))
    end

    return part.CFrame:PointToWorldSpace(clampedPoint)
end
#7

just saying, that it works on the bounding box of the part not the part itself. So meshes won’t work right

#9

there is a get closest point on surface API, I didn’t know that

#10

Hello there ;]

Did you find a solution?

I had an idea that might work, by using the tan function.

The only downside is that this method might work only on cubes or rectangles, and only if the point is outside the part. (But this can be solved by getting the normalized direction and multiplying it)

Lets start with the X coordinate

The first step would be to calculate te angles between each cordinate of the cube and the point.
I’m kinda new to programing so i don’t know exactly how to do it

Next step is to calculate the tan value with math.tan(AngleX)

Next step is just trigonometry

local DisX = Part.Size.X / 2 -- Part.Size is here to get the distance between the center and the part's face

local PosX = TanX *  DisX

Next we find the distance in the X Axis

local DistanceX = math.sqrt(DisX^2 + PosX^2)

Just repeat this for each coordinate and do more trigonometry to get the full distance

local Distance = math.sqrt(DistanceX^2 + DistanceY^2 + Distance.Z^2)

Hope this helps ;]