Collision group does not exist, but the same code doesnt error in my other game. I wasn't pleased with my terrain so made a new file , created a more desirable terrain. yet in the 'new' file the collision group doesnt seem to exist. What may be the cause?
local function setCollisionGroup(parent, group)
for _,part in pairs(parent:GetChildren()) do
if (part:IsA("BasePart") or (part:IsA("MeshPart"))) then
PhysicsService:SetPartCollisionGroup(part, group)
end
end
end

2 comments
Did you try checking to see if you made the collision group in the new game?
should have you 2 hours ago, would have saved me some. You were right, I did forgot to add the group. Thanks!