The Calculus Affair
This is the animated 'film' (actually a TV series edited together into one 57-minute chunk) that I referred to when I read the book. My comment that it "bears no resemblance to the book whatsoever" was based on the series' Wikipedia entry, which says the following:
The Calculus Case (The Calculus Affair) was the most altered series, the changes amounting to a completely different story altogether.
Having watched it, I can say that's utter poppycock. Lots has been changed, certainly, but all of the set piece action sequences remain, and the fundamentals of the plot are the same too. One character has been cut, there's a bigger role for the Thom(p)sons, and who gets where when and how has been tweaked, but it's still about Bordurians kidnapping Calculus because he's invented a sonic weapon, and Tintin and Haddock travelling to Borduria to rescue him from a castle-prison.
It's actually pretty good, too, with a nice clean animation style and some fun antics. Absolute purists must hate the deviations, but it's mostly in the right spirit.
