Are 3DCG-based animes cheaper to produce? I've been noticing that CG in anime has becoming more popular. Recently, I've watched several shows that have almost fully 3D animation.

Arpeggio of Blue Steel and Knights of Sidonia:




I've also noticed it appearing to smaller effect in parts of other shows, such as Girls Und Panzer, when the focus is not directly on the characters:



It seems that primarily mechanical objects are done with 3D technologies as the measurements are exact. This doesn't surprise me, but human characters are notoriously hard to do with computer graphics - see the Uncanny Valley . For this reason I would have thought making 3d anime characters (who don't even have normal human proportions) would be expensive to do right.

Is the reason anime companies are starting to use this technique more for characters, that it has become cheaper to implement? Or is there another reason for this slowly increasing popularity?
I don't know if 3DCG is cheaper, but we can compare differences in 2D and 3D process to identify possible savings.

First, lots of the anime creation process is same. Directing, writing, character design, screenplay, dubbing, marketing are all same. So there are no savings there.

Second, 3DCG has bigger up-front cost, because you have to create the 3D models. This is especially problematic for characters, if it is main focus of the show. It is less a problem for mechanical stuff and backgrounds, because they are easier to model and many shows already use 3D for those.

Third, the animation. Animating mechanical things is easy because you have low number of moving parts and their order of freedom is low. Humanoids on the other hand are hard to animate and even harder if you want the movement to seem natural. And the complexity goes up as character interact between each other and environment.

So if the show is primarily animating mechanical things moving around then there is big chance of saving some money. If the show is about characters and their interaction, then I guess there is no much saving and the primary purpose of using 3DCG is to maintain consistency.