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Creating a Region3 around a model?

Asked by

7 years ago

How would I go about creating a Region3 around a model? Right now, I have this, but it doesn't go around the entire model:

01local function getC(obj, t)
02    if obj:IsA("Model") or obj:IsA("Folder") then return getC(obj:GetChildren()[1], t) end
03    if obj:IsA("BasePart") then
04        if t=="X" then
05            if obj.Position.X >= 0 then
06                return obj.Position.X + (obj.Size.X/2)
07            else
08                return obj.Position.X - (obj.Size.X/2)
09            end
10        elseif t=="Y" then
11            if obj.Position.Y >= 0 then
12                return obj.Position.Y + (obj.Size.Y/2)
13            else
14                return obj.Position.Y - (obj.Size.Y/2)
15            end
16        elseif t=="Z" then
17            if obj.Position.Z >= 0 then
18                return obj.Position.Z + (obj.Size.Z/2)
19            else
20                return obj.Position.Z - (obj.Size.Z/2)
21            end
22        end
23    end
24    return false
25end
26 
27for _,v in pairs(model:GetChildren()) do
28    local gX = 0
29    local gY = 0
30    local gZ = 0
31 
32    local gXl = 1000000000
33    local gYl = 1000000000
34    local gZl = 1000000000
35 
36    for _,q in pairs(v:GetChildren()) do
37        x = getC(q, "X")
38        y = getC(q, "Y")
39        z = getC(q, "Z")
40        if x then
41            if x > gX then gX = x end
42            if x < gXl then gXl = x end
43        end
44        if y then
45            if y > gY then gY = y end
46            if y < gYl then gYl = y end
47        end
48        if z then
49            if z > gZ then gZ = z end
50            if z < gZl then gZl = z end
51        end
52    end
53 
54    local uc = Vector3.new(gX+1000, gY+250, gZl+1000) --uppercorner
55    local lc = Vector3.new(gXl-1000, gYl-250, gZl-1000) --lowercorner
56 
57    local tbl = {
58        ["model"] = v,
59        ["region3"] = Region3.new(uc,lc),
60        ["upper"] = uc,
61        ["lower"] = lc
62    }
63    table.insert(_G.rs, tbl)
64end
 View all 64 lines...

Any help is appreciated.

1 answer

Answered by

XAXA 1569

7 years ago

Edited 7 years ago

01function GetModelAABB(model)
02    local modelMin = nil
03    local modelMax = nil
04    for _, v in pairs(model:GetChildren()) do
05        if v:IsA("BasePart") then
06            local cf = v.CFrame
07            local size = v.Size
08            local baseCf = cf * CFrame.new(-size/2)
09            for x = 0, 1 do
10                for y = 0, 1 do
11                    for z = 0, 1 do
12                        local testCorner = (baseCf * CFrame.new( size * Vector3.new(x, y, z))).p
13 
14                        if not modelMin then
15                            modelMin = testCorner
16                        end
17 
18                        if not modelMax then
19                            modelMax = testCorner
20                        end
21 
22                        modelMin = Vector3.new(
23                            math.min(modelMin.x, testCorner.x),
24                            math.min(modelMin.y, testCorner.y),
25                            math.min(modelMin.z, testCorner.z)
26                        )
27                        modelMax = Vector3.new(
28                            math.max(modelMax.x, testCorner.x),
29                            math.max(modelMax.y, testCorner.y),
30                            math.max(modelMax.z, testCorner.z)
31                        )   
32                    end
33                end
34            end
35        end
36    end
37 
38    return Region3.new(modelMin, modelMax)
39end
 View all 39 lines...

This returns a Region3 that hugs the model.

Get each corner of each part in the model, and get the minimum/maximum in each dimension. Return a Region3 made out of these. I have not run this, but in theory this should work. Make sure model is actually a model, otherwise this will error.

EDIT: Also, parts are not examined recursively. You may want to modify this so that it does.

EDITEDIT: Tested and found a missing parenthesis. It works.

Thank you! If I had the reputation to upvote, I would. This was exactly what I was looking for. BreadyToCrumble 121 — 7y

I appreciate that you at least tried, though. XAXA 1569 — 7y

This is already a core function, model:GetExtentsSize(). It's not perfect, but yours is even less so. cabbler 1942 — 7y

@cabbler GetExtentsSize only gives me the size of the box around the model, it doesn't return the actual region. BreadyToCrumble 121 — 7y

View all comments (2 more)

"It's not perfect, but yours is even less so." I highly doubt that. Do you have any proof? My implementation covers the definition of an axis-aligned bounding box (it's as good as we're going to get in Roblox, anyway, without getting the vertices of a mesh). Moreover, GetExtentsSize() is dependent on the rotation of a model's PrimaryPart (which is arbitrary), and rotations are no good for Region3s XAXA 1569 — 7y

Excellent, thanks! I've been struggling for ages trying to line up models and non of the built in functions seem to be up to the task! Even just trying to put a 'car ON the road' is a nightmare! Spedley2142 0 — 7y

Creating a Region3 around a model?

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