I made an animated barrier thing that uses :SetPrimaryPartCFrame() to move portions of the barrier. Here is its progress over time:

When I first open it up in run mode:

I minimized studio and left it alone for a while. A little short of an hour later and it’s turned into this:

Notice how some of the pieces are no longer connected. Leaving it for a day resulted in this:

Here is a picture that shows the individual models:

```
local interpolation = require(script.CFrameInterpolator)
local root = script.Parent
local center = root.Center
local arms = {root.Arm1, root.Arm2}
local feet = {root.Foot1, root.Foot2, root.Foot3, root.Foot4}
local delta = {
sideFoot = CFrame.new(0, 0, -0.15198);
otherFoot = CFrame.Angles(0, math.pi/2, 0);
arm = CFrame.Angles(-math.pi/2, 0, 0);
}
--currentSize = 104.18369293213
root = script.Parent
function getModelScale()
return root.Center:GetModelSize().magnitude
end
function toUnitCFrame(cframe)
return (cframe - cframe.p + cframe.p/getModelScale())
end
function fromUnitCFrame(cframe)
return (cframe - cframe.p + cframe.p*getModelScale())
end
local offsets = {
foot1 = center:GetModelCFrame() * fromUnitCFrame(CFrame.new(2.37998208e-007, -0.40409416, 0.191968918, -1.00000036, 1.61602384e-006, -2.65690829e-007, 1.61602418e-006, 1.0000006, -2.98019387e-008, 2.65691085e-007, -4.47039739e-008, -1.0000006));
foot2 = center:GetModelCFrame() * fromUnitCFrame(CFrame.new(3.11228433e-007, -0.404094189, -0.191968471, 1.00000036, 1.61602384e-006, 2.65690829e-007, -1.61602418e-006, 1.0000006, 2.98019387e-008, -2.65691085e-007, -4.47039739e-008, 1.0000006));
foot3 = center:GetModelCFrame() * fromUnitCFrame(CFrame.new(0.0364743434, -0.456885636, -6.59071986e-007, -1.00000036, -4.47281536e-008, -1.48290587e-006, 1.4829061e-006, 2.15568534e-007, -1.0000006, 4.47284378e-008, -1.0000006, -2.00666733e-007));
foot4 = center:GetModelCFrame() * fromUnitCFrame(CFrame.new(-0.0364743061, -0.456885636, 3.84458644e-007, 1.00000036, 2.80591706e-007, -1.81424491e-006, -1.81424525e-006, 1.27260016e-008, -1.0000006, -2.80591991e-007, 1.0000006, 2.76281096e-008));
arm1 = center:GetModelCFrame() * fromUnitCFrame(CFrame.new(1.61106482e-006, 0.388737112, 0.137256429, 0.99999392, 1.6160194e-006, 8.68786856e-008, -1.61601292e-006, 0.999997735, 1.55712144e-006, -8.68760992e-008, -1.57202317e-006, 0.99999702));
arm2 = center:GetModelCFrame() * fromUnitCFrame(CFrame.new(1.24491373e-006, 0.388736904, -0.137257516, -1.00000036, 1.61602384e-006, -2.65690829e-007, 1.61602418e-006, 1.0000006, -2.18651941e-008, 2.65691085e-007, -3.67672293e-008, -1.0000006));
}
require(feet[3].ModuleScript)
require(feet[4].ModuleScript)
local startFootOffset = CFrame.Angles(0,0,0)
while true do
local interpolate1 = interpolation.new(offsets.foot1, offsets.foot1 * fromUnitCFrame(delta.sideFoot))
local interpolate2 = interpolation.new(offsets.foot2, offsets.foot2 * fromUnitCFrame(delta.sideFoot))
local interpolate3 = interpolation.new(offsets.foot3, offsets.foot3 * delta.otherFoot)
local interpolate4 = interpolation.new(offsets.foot4, offsets.foot4 * delta.otherFoot)
local interpolatea1 = interpolation.new(offsets.arm1, offsets.arm1 * delta.arm)
local interpolatea2 = interpolation.new(offsets.arm2, offsets.arm2 * delta.arm)
for i=1,25 do
feet[1]:SetPrimaryPartCFrame(interpolate1(i/25))
feet[2]:SetPrimaryPartCFrame(interpolate2(i/25))
feet[3].Foot:SetPrimaryPartCFrame(interpolate3(i/25))
feet[4].Foot:SetPrimaryPartCFrame(interpolate4(i/25))
arms[1]:SetPrimaryPartCFrame(interpolatea1(i/25))
arms[2]:SetPrimaryPartCFrame(interpolatea2(i/25))
wait()
end
for i=24,0,-1 do
feet[3].Foot:SetPrimaryPartCFrame(interpolate3(i/25))
feet[4].Foot:SetPrimaryPartCFrame(interpolate4(i/25))
feet[1]:SetPrimaryPartCFrame(interpolate1(i/25))
feet[2]:SetPrimaryPartCFrame(interpolate2(i/25))
arms[1]:SetPrimaryPartCFrame(interpolatea1(i/25))
arms[2]:SetPrimaryPartCFrame(interpolatea2(i/25))
wait()
end
end
```

None of that code sets the CFrame of any of the individual components inside those models. The only thing that moves them is :SetPrimaryPartCFrame(). Regardless of what I do with :SetPrimaryPartCFrame(), the models that make up the barrier should stay together – they don’t. This is an issue with :SetPrimaryPartCFrame() that causes components to gradually offset from each other over time.