Magnetic Resonance imaging (MRI) is a medical imaging procedure which uses strong magnetic fields and radio waves to produce cross sectional images of organs and internal structures of the body. Three dimensional (3D) models of CT is available and it has been practiced by almost all radiologists for pre-diagnosis. But in MRI still there is a scope for researcher to improvise a 3D model. Two dimensional images are taken from different viewpoints to reconstruct them in 3D, which is known as rendering process. In this Book, I, proposed a rendering concept for Medical (Brain, cardiac, Knee MRI) images based on iso values and number of marching cubes. Designer can place colors and textures over the 3D model to make it look realistic. This makes it easier for people to observe and visualize a substance in a better sense. The algorithm basically works on triangulation methods with various iso value and different combination of marching cube pairs. As a result of an application of marching cube concept, volumetric data (voxels) is generated. Voxels are then arranged and projected to visualize a 3D scene. Approximate processing time for various iso values are also compared in this book.