Visualization: The Art of Illumination

Paul TiceMultimedia, Rendering, Animation

A few years ago I was at an American Institute of Architects (AIA) conference entitled ‘The New Now‘ held at the beautiful Salishan Resort on the Oregon Coast. It was fun to experience brilliant design minds coming together to speak about architecture in a way not unlike poetry. It was clear that many of the guest speakers were well-practiced in linking aesthetic language with physical descriptions of infrastructure. Indeed this language has been instilled in the very discipline of architecture:

…if we erect a dwelling which may appear adapted to the wants, and sufficient for the comfort, of a gentle heart and lowly mind, we have instantly attained our object; we have bestowed animation, but we have not disturbed repose.

The architects who spoke at the conference talked extensively about environment and light within spaces. They proselytized through photos the beauty and efficiency of natural light. Short of missing walls or a transparent roof, it was hard to imagine spaces that could have any more illumination.

It was this sort of aesthetic experience that drew me into the art world in the first place. I have always been intrigued by the ways light can be designed into architecture. As a boy, I recall going to a science museum that was several stories tall and wide open. I remember staring at the ceiling until my neck hurt, taking in the beauty of the structural elements that were laid bare to add to the somewhat futuristic feel of the space, illuminated by natural light.

Oregon Museum of Science and Industry (OMSI)

In art, some of the most realistic representations of reality are made possible only by the ability to capture light.

Oil Painting by Eric Christensen
Oil Painting by Yigal Ozeri

Among the most common tools for working with light in renderings include settings with ‘direct illumination’ and ‘indirect illumination’ (aka, global illumination or radiosity). Within these settings are a variety of setups users can establish to include terms like “Ambient Occlusion”, “Ray Tracing”, “Caustics”, and others.

Ambient Occlusion Rendering
Ray Traced Rendering – Lord of the Rings Motion Picture

Direct and indirect illumination has a few basic principles that carry across all computer rendering disciplines that are useful to know. As their names imply, these terms mimic the real world. Direct illumination, algorithmically speaking, is “simple”. This setting allows you to set a light source such as a spotlight, solar light, point light, etc., and cast it onto objects within your 3D scene. From this, shadows are thrown to indicate areas that have obscured the light from passing through. So any solid surface typically will cast a shadow with this setting. Indirect lighting will create a level of ambiance in your scene as light is bounced off of objects. This helps with creating photorealism. Another fascinating note (to me) is the way radiosity actually works. Instead of relying on a light source to calculate illumination, each pixel on each surface actually sees other pixels on other surfaces. One way this has been explained is to imagine each pixel having ‘x’ number of arrows pointing in many directions. These arrows shoot off eventually landing on other pixels, essentially observing them and reading their information such as hue, value, etc. So for this setting – for the radiosity setting in whatever render engine you may be using – increasing the number of indirect rays will increase the resolution of your rendering. Here is a great TUTORIAL on the way this method works which can help you understand your render settings better to create that wow-factor you’ve been looking for.

Render illumination on textures or areas in which you are looking to achieve relief (depth and height on surfaces), are highly dependent on surface normals, which I mentioned in a previous blog (See ‘Visualization: MODO-tion‘).

Overcoming the Time Factor
Similar to fine art, bringing light into the computer graphics world can require years of training and patience for the process. Some wait for a canvas to dry before applying the 29th glaze, while others wait for several hours (or days, depending on hardware), to see whether their attempts were successful. This process can be quickened by the use of current software features such as distributed rendering. Another ‘quickening’ for render times, can be leveraged through the use of render farms – but don’t let me try to tell you about it. No, I think Mr. Buck Bunny does a much better job…(note that Renderfarm.fi is no longer available yet this video explains renderfarms in general)

Renderfarm Bunny

Here are some up-to-date renderfarm options to consider:

ToPa 3D~