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How to make a part face the closest side of another part?

Asked by

SummerEquinox 643

6 years ago

Edited 6 years ago

Alright, so before beginning this post:

this is absolutely not the most efficient way to do this
i want to understand why THIS method is not working, not for a more efficient method
this project does NOT include the top and bottom surfaces of the init part

Alright so: I have a part which I will drag around my Baseplate - and a reference part which stays in a single position on the Baseplate. I don't want to use cf.new(vector,vector) at the closest side - I just want it to FACE the closest side, not the middle of the closest side.

Currently this is what I have, and I feel the issue lies in my handling of rotations toward the end:

01local init_part = workspace.Init
02local ref_part = workspace.Ref
03 
04local points = {}
05 
06local sub_x = init_part.Size.X / 2
07local sub_z = init_part.Size.Z / 2
08 
09local two, four = init_part.Position + Vector3.new(sub_x,0,0), init_part.Position - Vector3.new(sub_x,0,0)
10local one, three = init_part.Position + Vector3.new(0,0,sub_z), init_part.Position - Vector3.new(0,0,sub_z)
11 
12function determine_closest_side(from_part)
13    local one_dist = (from_part.Position - one).Magnitude
14    local two_dist = (from_part.Position - two).Magnitude
15    local three_dist = (from_part.Position - three).Magnitude
16    local four_dist = (from_part.Position - four).Magnitude
17 
18    local distances = {one_dist, two_dist, three_dist, four_dist}
19    table.sort(distances)
20 
21    local closest = distances[#distances]
22 
23    if one_dist == closest then
24        return one
25    elseif two_dist == closest then
26        return two
27    elseif three_dist == closest then
28        return three
29    else
30        return four
31    end
32end
33 
34while wait(1) do
35    local cframe_construct = CFrame.new(init_part.Position, determine_closest_side(ref_part))
36 
37    local part = Instance.new("Part")
38    part.CFrame = cframe_construct
39    part.Anchored = true
40 
41    local y_orientation = part.Orientation.Y
42    local solved_orientation = y_orientation - math.pi
43 
44    ref_part.CFrame = CFrame.new(ref_part.Position) * CFrame.Angles(0,solved_orientation,0)
45end
 View all 45 lines...

If you want to experiment with this:

1) Make two parts in Workspace

2) Name one part Ref, and the other part Init

3) Put this script in SSS

4) Drag Ref around the Init part in Run mode.

Hopefully this is a decent explanation - but if you have further questions just make a comment.

1 answer

Answered by

SteamG00B 1633

6 years ago

Edited 6 years ago

Edit: So this I have tested, it uses dot products to calculate the vector perpendicular to the original part (I'm pretty sure it was the original part, couldn't tell for sure because of the rate the parts kept spawning in).

01while wait(1) do
02    local cframe_construct = CFrame.new(init_part.Position, determine_closest_side(ref_part))
03 
04    local part = Instance.new("Part")
05    part.CFrame = cframe_construct
06    part.Anchored = true
07    part.Parent = workspace --just added this in so I could see where the parts were for testing purposes
08 
09    local v = init_part.Orientation
10    local u = ref_part.Orientation
11    local lookVector = Vector3.new(v-(u*v:Dot(u)/u:Dot(u))) --dot product magic that gets a perpendicular vector to the original part
12 
13    ref_part.CFrame = CFrame.new(ref_part.Position) * CFrame.Angles(lookVector.X,lookVector.Y,lookVector.Z)
14end

The orientation being incorrect does not involve the length of the yielding between happenings. If it did I would use RunService. SummerEquinox 643 — 6y

So I'm not sure if this got it to face the right part, but it did face towards a part when I moved it around in a circle. SteamG00B 1633 — 6y

How to make a part face the closest side of another part?

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