GD&T RULE #1 and ENVELOPE PRINCIPLE ( E )

Very important Rule #1 and Envelope Principle (E) is step-by-step explained.
What is Principle of Perfect form at MMC - basic learning of the requirement
Also difference between ASME & ISO discussed.
How Independency Principle Symbol I over-ride the Rule #1.
What conditions are where Rule #1 is not followed.
What are other constraints to over ride Rule #1.
What is