Pmx Editor is described as 'PMX Editor is for editing 3D model data to be used in MikuMikuMoving ' and is a 3D Modeler in the Photos & Graphics category. There are three alternatives to Pmx Editor for a variety of platforms, including Windows, Android, Android Tablet, iPad and iPhone. The best alternative is VRoid Studio, which is free. Other great apps like Pmx Editor are MikuMikuDance (Free) and MikuMikuMoving (Free).
pixiv has released "VRoid Studio", a character maker that allows users to create, in easy steps, 3D model characters which can be used in various VR\AR platforms as well as the production 3DCG animation and games.