Photon Mapping is a rendering technique which can render indirect illumination and caustics, two lighting effects generally associated to radiosity or global illumination.
While Photon Mapping is an efficient algorithm, it is nevertheless much slower than ray tracing alone. A good understanding of the effects of each of the numerous parameters that control its operation is necessary in order to get the best tradeoff between a desired quality and an acceptable render time and this tradeoff is greatly dependent on the scene to be rendered.
With this tutorial, I will try to explain how Photon Mapping works and what are the effects of each of the different parameters which affect the resulting render quality and time. My hope is that with this knowledge, you will be better armed to more efficiently use the Photon Mapping renderer.
However, each scene and situation being very different and particular, some experimentation will nevertheless be necessary in order to acquire a full intuitive feel for its working. Photon Mapping is not easy to use and requires the acquisition of a lot of new knowledge. If you are looking for quick recipes then Photon Mapping might not be for you.
Table of content
Introduction
What can be expected from Photon Mapping
An overview of Photon Mapping
How it fits within the renderer families.
Fundamentals of Photon Mapping
A quick description of the Photon Mapping algorithm.
Monte-Carlo
An overview of the Monte-Carlo estimation technique.
Photon Mapping parameters
Examines all the Photon Mapping related parameters found in A:M.
Setup for Refractive Caustics
How to setup a scene and its parameters to render caustics from transparent and refractive objects.
Setup for Reflective Caustics
How to setup a scene and its parameters to render caustics from reflective objects.
Setup for Indoor Indirect Illumination
How to setup a scene and its parameters for indoor indirect illumination renders.
Setup for Outdoor Indirect Illumination
How to setup a scene and its parameters for outdoor indirect illumination renders replacing a skylight.
Finding the Optimal Parameters
A procedure to help determine the proper set of parameters for a scene.
Conclusion
A wrap-up and some other ideas.
Photon Bloopers
A few renders that went wrong during the development of the Photon Mapping rendering engine. |
