jobel , yes they are 3d models, the camera is pointed at the model and image or sequence are rendered out, not really a screenshot,
basic shapes, i mean spheres, squashed spheres, cilinders, some programs have special primitives with deformers and all that
While i said you can get this result, i mean if you have 3d experience you can get close to something like this, in order to get these full worklow, with colors,light, bumpmap, animation, it takes time..., and if you have to learn all the concepts first... i would only spend time on it if you really want to learn it. if not you better off finding other solutions,.. program used not sure, any 3d program would do if your good with it.
yeah well i paint/draw with my old trusty wacom intuos, have it for years now.., you have a digital pen?