How do I check if a part is touching another part?
So, I have a part that gets created like a selection box, which can be found here .
Since I'm using this as a selection box, I need to find out what parts it's touching. I don't want to use GetTouchingParts because the parts that are to be selected can't be canCollide true.
local mags = {}
for i,v in pairs(game.Workspace.Map:GetChildren()) do
if v.Name == "Cell" then
local mag = (v.Position-part.Position-part.Size).magnitude
table.insert(mags,#mags+1,mag)
print(mag)
end
end -- I also tried taking out -part.Size
The above isn't reliable. Anybody have any ideas? Any help would be appreciated.
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1 answer
I actually ran around writing a bunch of code for testing if a point is inside a part using dot products only to find this chunk of code by Anaminus
local function PointInsidePart(Part, Point)
--- Return's whether a point is inside of a part.
-- @param Part The part to check. May also be a table with a .Size and .CFrame value in it.
local PartSize = Part.Size/2
local RelativePosition = Part.CFrame:pointToObjectSpace(Point)
--print(RelativePosition, PartSize)
if not (RelativePosition.X >= -PartSize.X and RelativePosition.X <= PartSize.X) then
return false
elseif not (RelativePosition.Y >= -PartSize.Y and RelativePosition.Y <= PartSize.Y) then
return false
elseif not (RelativePosition.Z >= -PartSize.Z and RelativePosition.Z <= PartSize.Z) then
return false
end
return true
end
Anyway, here is the full code with some comments for explanation on my code
local function getVertices(part)
local pos = part.Position
local size = part.Size
local cf = part.CFrame
local vertices = {}
-- get all 8 vertices
vertices[1] = cf * CFrame.new(size.x*0.5, size.y*0.5, size.z*0.5)
vertices[2] = cf * CFrame.new(size.x*-0.5, size.y*0.5, size.z*0.5)
vertices[3] = cf * CFrame.new(size.x*0.5, size.y*-0.5, size.z*0.5)
vertices[4] = cf * CFrame.new(size.x*0.5, size.y*0.5, size.z*-0.5)
vertices[5] = cf * CFrame.new(size.x*-0.5, size.y*-0.5, size.z*0.5)
vertices[6] = cf * CFrame.new(size.x*0.5, size.y*-0.5, size.z*-0.5)
vertices[7] = cf * CFrame.new(size.x*-0.5, size.y*0.5, size.z*-0.5)
vertices[8] = cf * CFrame.new(size.x*-0.5, size.y*-0.5, size.z*-0.5)
return vertices -- return them
end
local function PointInsidePart(Part, Point) -- Credit for this goes to anaminus
--- Return's whether a point is inside of a part.
-- @param Part The part to check. May also be a table with a .Size and .CFrame value in it.
local PartSize = Part.Size/2
local RelativePosition = Part.CFrame:pointToObjectSpace(Point)
--print(RelativePosition, PartSize)
if not (RelativePosition.X >= -PartSize.X and RelativePosition.X <= PartSize.X) then
return false
elseif not (RelativePosition.Y >= -PartSize.Y and RelativePosition.Y <= PartSize.Y) then
return false
elseif not (RelativePosition.Z >= -PartSize.Z and RelativePosition.Z <= PartSize.Z) then
return false
end
return true
end
function doPartsCollide(part0, part1)
local vertices = getVertices(part0) -- get all the vertices (corners) of our part
for _, vertex in pairs(vertices) do -- iterate
if PointInsidePart(part1, vertex.p) then -- if point is inside
return true -- part collided
end
end
return false -- didn't collide
end
We get all the vertices by using the size vector and the position. It's in cframes to account for rotation.
Anaminus' code is very elegant and compares the size of the part and position(of the point in object space) to determine whether or not the point is outside of the part. Returning true if it isn't.
The we get an array of the first part's vertices and iterate through it. We check if this vertex is inside the other part and return true if it is.
I haven't slept in a while, so sorry if there are any mistakes.