There's a lot of parts in this model and i want them all to do the transparency loops at the same time, but it seems to be only doing it 1 at a time?
for i,v in pairs(workspace.Model:GetDescendants()) do
if v:IsA('BasePart') or v:IsA('Decal') then
for i =1,10 do
local num =0
repeat wait()
num = num + 1
v.Transparency = v.Transparency + 0.1
until num == 9
local num =0
repeat wait()
num = num + 1
v.Transparency = v.Transparency - 0.1
until num == 9
end
v.Transparency = 1
end
end
end

2 comments
Would it mess up your build to make the parts a single union?
if v.ClassName == "Part" then