Final Image

By: Leoniel Lopez and Lex Lacson

Size: 1024x768, 256 samples/pixel, 50000 global photons, 25000 caustic photons, 97895 triangles

 

Inspiration Image

Photo and permission by: Ahmad Nizam Awang

For our final project, we wanted to render a scene from nature, and after searching for a few pictures, we came across this picture by Ahmad Awang. We were really interested in rendering this picture because it consists of a translucent leaf with caustics from dew drops that shine through. It required a few advanced rendering techniques which are listed below.

 

Features

Depth of field

   

To simulate depth of field, multiple random disc samples were taken from the camera eye, which were then traced through the focal plane. Areas behind and in front of the plane become blurred. Our scene focused on the center of the leaf.

 

Photon mapping

 

Photon mapping was used to simulate the caustics of dew drops on the leaf and also the illumination of the leaf. The caustic photon map stores photons that were reflected or refracted off of a specular material onto a diffuse material. In our scene, our caustics were created by the dew drops on the leaf. Also, the global photon map helped to illuminate the leaf.

Here is one of our photon maps. Red pixels are caustics and green is global

Here is our scene without photon mapping.

 

Bump mapping

 

Bump mapping by normal map was used to realistically texture and bump the leaf. We look up the value in the normal map and use it to determine how much we perturb the normal on the surface. We also had procedural bump mapping, but was not used for the scene.

 

Environment mapping

Here is the scene without environment maps. As you can see, environment maps contributed a lot to the scene.

 

Snell's Law/Fresnel Equations

 

Here is a scene using Fresnel's equation(left) and a scene without(right)

Snell's law and Fresnel's equation were needed to realistically simulate the refraction of water. Snell's law determines the direction of the refracted light and Fresnel's determines how much light is reflected or refracted by a refractive material.

 

Area Lights

 

Area lights were used to simulate soft shadows. Since the sun is the only lighting in the scene, an area light was necessary to depict it.

 

3D Modeling

 

Since there were not any nice leaf models online and we wanted to accurately portray the inspiration image, all models were modeled in Autodesk Maya and exported in obj format.