Did I get the angle correctly?

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#1

I tried getting the angle between Part A and Part B, Did I do it correctly?
The angle it outputted was 48 degrees

Here is the code:

local Key1 = game.Workspace.PartA
local Key2 = game.Workspace.PartB

local PosDiff = Key1.Position - Key2.Position

local XDiff = math.abs(PosDiff.X) -- 61.71
local ZDiff = math.abs(PosDiff.Z) -- 69.50
-- Hypothenus is 93, I didnt need it in the ATan formula.

print(math.deg(math.atan2(ZDiff, XDiff)) -- Output: 48

Here is a visual representation I did based off what I think is happening behind the scenes:
did I visualize it correctly?

angle
angle666×595 263 KB

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A few trigonometry questions that I am confused about, Am I thinking about it wrong?
#2

Resurface #1 - Status Unanswered

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#3

Hi again :wave:

I only think that solution would work in the first quadrant. The cool thing about atan2 is that it works in all 4 quadrants, but uses two numbers vs normal atan's single number. However it needs to know the signs of the input numbers (+/-), so taking the absolute value of the position difference removes important information that it needs.

Try it all around the circle, IMO it should only work without the abs. Other than that yeah it looks right, I think you even have the order of parameters to atan2 right which can be a bit confusing.

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#4

Hey, I removed the absolute value function.

Now the angle dont seem to fit in/match up, How is it being calculated?

The output is 132 degrees, shouldn’t it be 48 degrees: the way I mapped it out visually?

Edit (1)
Edit (1)852×646 279 KB

Code:

local Key1 = game.Workspace.Key1
local Key2 = game.Workspace.Key2

local PosDiff = Key1.Position - Key2.Position
local XDiff = PosDiff.X -- 69.50
local ZDiff = PosDiff.Z -- 69.50

print(math.deg(math.atan2(ZDiff, XDiff))) -- Output 132
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#5

Yeah, it definitely looks like 48 should be right. Can you try negating the 1st parameter to atan2? I.e. math.atan2(-ZDiff, XDiff). I think it’s the opposite of a normal coordinate system because Roblox’s front vector is (0, 0, -1) and not (0, 0, 1). You can see the XYZ axes in Studio using the View Selector (it’s really hard to see in this screenshot).

image

image

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#6

I tried negating the 1st parameter, it didnt work, then I tried the negatiting the X(Second Paramater) and it worked. The angle now displays properly,Thank you for assisiting.

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