I moved to math from computer science because I learned a lot more computer science in math than I did in computer science. you'll learn a whole lot more about three dimensions in linear algebra/multivariable calculus/vector calculus than in any of your computer science classes. All you need to know about from those computer science classes is learning APIs. So, want to work as a software developer/game programmer or something, that's fine I suppose, be a computer science major. But all you need to learn is how to work with APIs and those design patterns and stuff. But if you want to be a real computer scientist then it's all in the math.
Man, that's not true at all. Maybe not where you studied, but here I've had pretty intensive courses on algorithms, all the maths you mentioned, and computer theory in general as opposed to 'just learning the API'. I'm pretty good friends with some of the maths students here, and they've been shocked by the amounts of maths we have to do.
If your course is just learning the API however, then yeah, you'll probably not learn much, but this doesn't hold for the way Computer Science is taught around the world. With us, you're already expected to know the API.
Also, we usually do a shit load more writing than most Humanities courses at our University. Both analytical and reports.
I guess what I'm trying to say is, with Computer Science you're going to be learning a lot. Maths, how to write formally, how to deal with clients, team management, requirements analysis, effective algorithm solving, plus whatever else that you choose to study including the 3D animation. Of course, I guess this is all dependent on the way that your CS department decides to teach.