How to check if a part touched a model?

You have a few options here...

1 is an ugly method called magnitude, works best on circles:

if (part.Position-part2.Position).Magnitude < (whatever the size of part2 is, any axis) then
	print('in range')
end

You can loop it or whatever.

You can use region3, raycasting, .Touched, GetTouchingParts()

local part = workspace.Part
for _, v in pairs(part:GetTouchingParts()) do
	print(v.Name)
end

You can loop it again for the next time its touched

then theres the good old .Touched

part.Touched:Connect(function(obj)
	if obj:IsDescendantOf(workspace.Model) then
		print('model touched')
	end
end)

You can also do it the other way

for _, v in pairs(model:GetDescendants()) do
	v.Touched:Connect(function(obj)
		if obj == part then
			print('touched part')
		end
	end)
end

So uh, see which one helps you, gl bye