Non-photo realistic rendering techniques generally admits as painterly rendering, line art rendering, computer sketching and half toning. These techniques are widely used for producing stylized artificially looking drawings. Computer models in architecture are often targeted to photo-realism. Rendering techniques like ray tracing or radiosity can provide realistic looking results. The quality depends on the definition of material, light and environment. Applying real time virtual reality is still a compromise between navigation speed and photo-realism.