• Surface rendering uses light to create realistic 3D models.mountain montblanc rendering image by Pavel Losevsky from Fotolia.com
  
  Surface rendering is an alternative to volume rendering used to create 3D reconstructions using computer programs. These 3D reconstructions rely on light and algorithms that collect data from lasers directed at a particular surface, thus calculating the dimensions of an object. These techniques are often used in medicine to create 3D representations of organs in the human body. According to the University of California, different rendering techniques are used to create varying levels of detail.
  
  

Glyphs

• Scalar glyphs -- areas that can only hold one data value at a time -- are spheres or diamonds placed at every data point, which is a bit of information collected by the surface renderer. Then, the scale is determined by the data value, according to Georgia Tech. The color of the scalar glyph is based on the same scalar field that the data points are placed on or is based on a different scalar field. Vector glyphs are sometimes placed all over to represent data points.
  
  

Illumination Model

• When illuminating a surface, the surface rendering algorithm relies on the intensity of the calculations from the illumination model -- the model used to calculate the intensity of light on the surface of an object -- allowing light intensity to be determined on all pixels of the rendered image, according to Middle East Technical University. The surface rendering is sometimes applied to all visible surface points, allowing for a comprehensive construction of the object.
  
  

Cutting Plane

• A cutting plane is used to allow diagnostic technicians to see scalar data on a cross-section of the data volume with the cutting plane. The surface render finds a Cartesian grid -- a representation of a geometric space with no gaps -- on the plane and data values of the grid by placing new data points within the original data, according to Georgia Tech. The data is clearly visible through a color map.
  
  

Light Types

• The lighting models used by the surface renderer include the Quantum model, the wave model, and the geometric optics model. The lighting models take into consideration the interaction between the electromagnetic energy and the object's surfaces. The lighting model must take into account the reflections, refractions, translucency, caustics, surface texture and shadows that the human eye sees, according to Middle East Technical University. Refractions are changes in the direction of a light wave, translucency is the ability of an object to have light pass through it, and caustics is the overlapping of several light rays.
  
  

Orthogonal Slices

• Orthogonal slicers are used to focus on the effects of only two independent variables, according to Georgia Tech. This method tries to keep all of the other variables constant so that only the differences in the independent variables can be seen.