SPLINE3DCurve created from fixed points, either with a piece of wood or in computer graphics[------]! I studied those in one of my latest classes, surprised to see that answer. SARAN14AIt's used in some film production [hehehehe][-----] was a gimme... for me. A less mean constructor would have used SARAH and SHE instead of SARAN14AIt's used in some film production [hehehehe][-----] and SNO12D___ Balls [look, an American treat that isn't OREO!][---], but you know, the FILM-themed contest. BEATLEMANIA32A1960s affliction that originated in the UK[-----------] is a great bonus entry and I wish I could include some long bonuses in my contest submission but my themers are grid-spanners with the worst letter placement ever. My grid just doesn't want to fill itself nicely.
The GNC16DVitamin retailer based in Pittsburgh, PA that's now owned by a foreign corporation [and which appears literally in this clue][---]/RENOS18AExtensions and redecorations, in short *[-----] crossing gave me some trouble but I'm not the one who decided to stack three theme answers.
Unrelated to this puzzle: If you want, you could give me your email address so that I can send you the COW candidates from last week. I sent them to @mike
and they're probably in the spam folder, AGAIN.