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In the last two decades virtual reality (VR) simulations have had revolutionary effects on many fields such as medicine, architecture, science, financial, and military applications. On the contrary, in medicine, the applications of VR are not as extensive as in other fields. However, realistic VR surgery simulations are in high demand as a result of offering risk-free training environments for physicians. The necessity of realism compels researchers to adopt physics-based models and haptic renderings that place extra computation burdens on real-time rendering pipelines. In this study, we investigate the usability of already built-in physics-based models in physics/or game engine PhysX library, for scooping operations in artificial cervical disc replacement (ACDR) surgery. The motivation behind our work is twofold. First, intricacies involved in ACDR surgery are introduced and the fundamental components towards the development of a surgical simulator are addressed. Second, an on-going framework development is introduced for the scooping action based on the PhysX library which provides optimized and physics-based methods for a plausible simulation. Our simulator framework integrates a haptic device into the PhysX environment for force feedback in order to increase plausibility.

One of the essential components of a virtual reality surgical simulation is deformation. Deformations in computer graphics and surgical simulations are commonly modeled with three different approaches e.g. geometry based methods, Finite Element method(FEM), and Mass-spring Method (MSM). The geometry based methods are quite fast and visually appealing. Late two methods take the physics of deformation into consideration. Even though the FEM results in more physically realistic deformations, a significant drawback of this method is its expensive computation cost and vulnerability to surgical procedures such as incision. However,MSM is relatively computationally inexpensive.Because of the real-time physics based behavior of MSM, it is widely accepted by surgical simulation community. This study summarizes deformation simulation methods and their pros and cons for surgical simulations. Moreover, because of wide usage of the MSM, optimized data structures for MSM are provided and analyzed under different deformation settings.

A process of determining whether two or more bodies are making contact at one or more points is called collision detection or intersection detection. Collision detection is inseparable part of the computer graphics, surgical simulations, and robotics. There are varieties of methods for collision detection. We will review some of the most common ones. Algorithms for contact determination can be grouped into two general parts: broad-phase and narrow-phase. This paper provides a comprehensive classification of a collision detection literature into the two phases. Moreover, we have attempted to explain some of the existing algorithms which are not easy to interpret. Also, we have tried to keep sections self-explanatory without sacrificing depth of coverage.

Augmented reality (AR) system is a virtual environment that overlays the computer generated graphics on real-world view. A typical AR system consists of optical motion tracking and capturing. The main problem in such a system is minimizing error of mapping the movements of the actor in real domain to the virtual model. To do that, the position of markers attached to the actor needs to be carefully selected and mapped to the virtual counterpart. This one-to-one mapping process is called registration. In this regard, virtual and real domains should be aligned correctly. Any minute error in registration of these two domains results in degrading of the realism e.g. wrongly registered objects floating through each other. Current registration method for optical motion capture systems requires time-consuming and tedious manual processing. To overcome this problem, we present two-way (virtual object to real domain and real domain to virtual object) semi-automatic registration method. With our method instead of priory determining positions of markers on the physical object, we determine markers' positions (extreme points found by our application) on the virtual object and then locate markers at the approximate positions on the real object. By tracking the markers in the following step, we get markers' positions in real domain and change virtual domain's markers' positions accordingly to reduce error. Results show that our system solves the registration problem and prevents unrealistic jittering and flickering effects due to misalignment.