This paper presents a Mixed Reality environment, named Virtual Orthopedic LABoratory (VOLAB), which permits to emulate an orthopedic lab and design lower limb prosthesis, in particular, the socket component. The proposed solution is based on low cost devices (e.g., Microsoft Kinect) and open source libraries (e.g., OpenCL and VTK). In detail, the hardware architecture consists of three Microsoft Kinect v2, Oculus Rift for 3D environment visualization and Leap Motion device for hand/fingers tracking. The software development has been based on the modular structure of the prosthetic CAD system, named Socket Modelling Assistant (SMA) and modules have been developed to guarantee the communication among the devices and the performance. Finally, preliminary tests are illustrated as well as results reached so far and future development.