What is the name of this progam

Oh wow thanks for using my image! (bottom one). Alright, so the first one is MMD a.k.a. MikuMikuDance that one is the animation tool. The bottom one is garrys mod. It is not an animation tool it is a sandbox game. The bottom image I took is when the model was firat released. It was awesome to use! So if u want to animate, use MMD. If you want to toy around with the models, use Garry's Mod.

Oh! Also, if u have a windows computer, the model is also in SFM which is WAAAAAAY better than MMD so I suggest you use SFM.