Archive for March, 2010

CORNFORD & CROSS / LEAF RENDERS

March 28, 2010

Last month I was asked by Cornford & Cross to help visualize one of their proposed projects. They were interested in commissioning a digital artist to accurately model and render a dying English Oak tree in the court yard of Milton Keynes Shopping Centre, reproducing it in all it’s summer glory and displaying the billboard sized image within the shopping centre, mirroring the large advertising posters around the new and sterile complex.

Unfortunately the project never materialized but the preliminary renders of leaves I did proved good practice in simulating organic forms within Maya. As I am currently deep in the production phase of my film, it is interesting looking back and seeing how useful this exercise was in developing my knowledge of SSS (Sub-Surface-Scattering) shaders to a create realistic plant material.

Advertisements

PHOTOGRAPHIC EXPOSURE CALCULATOR / 1929-1930

March 24, 2010

While foraging through the debris of an East End market I found this wonderful photographic handbook from the late 1920’s published by Burroughs Wellcome & Co. The small document is filled with useful information designed to assist the photographer at every stage of his work. From essential facts about lenses to mixing chemicals and developing bromide paper, this book also comes with a diary and monthly light tables. At the back is the Exposure Calculator, a wheel that gives the photographer the correct exposure in seconds or fractions of a second depending on the type of shot they are taking (studio, distant landscapes, cloud cover…etc).

It’s fascinating to see how simply this book could predetermine depending on the time of year the suitable lighting conditions within which to take the perfect picture. Through understanding the principles of daylight the cinematographer could gauge very accurately what exposure would suite them best. Before the days of electronic lighting meters we relied so much on the clockwork cycles of natural light to provide this fundamental information for film and photography.

LIGHT DRIVEN PARTICLE SIMULATION / V.01

March 14, 2010

Having completed a rough storyboard for my final piece I’ve started to play around in Maya with different dynamic lighting setups. Because the premise of the work deals with the photobiological effect I am keen to create a lighting rig that could use its intensity to drive the animation of certain objects and simulations. The playblast below shows a point light that when turned on directly affects the turbulence of the particles. When the light is off the particles are static, but when illuminated they move quickly around the scene, the faster they move the longer their trial.

In the Hypergraph of Maya I connected a light source to the multiply/divide node which fed straight into the magnitude value of the turbulence field. For the time being this simply gives me a flexible and effective lighting rig that I can use to affect the dynamic properties of anything in my scene. However this is still faking the photoperiod effect in that the object is merely connected through the intensity value of the light source. To take this a step further I intend to follow up a more physically accurate network possibly using a surface luminance node to calculate the exact amount of light falling on a surface by using this value to drive the motion, scale, texture….etc.

PHOTOBIOLOGY

March 14, 2010

Photobiology is the scientific study of the interactions of light with living organisms. The field includes the study of photosynthesis, photomorphogenesis, visual processing, circadian rhythms, bioluminescence, and ultraviolet radiation effects. Rather than focusing on the effects of natural light I am more interested in the physiological effects of artificial light and how this interrupts the Photoperiod Effect (plant and animal response to length of day and night). During my research I have come across a number of journals on the internet that deal with this area of study. The Influence of Incandescent Light on Reproductive and Physiological Responses of Bovine Bulls as carried out by J.D. Roussel is an experiment in which a number of bulls were exposed to 14 hours of artificial light a day while the rest of the herd continued to graze under natural illumination. The results showed that an increase in exposure to light produced a greater reproductive response that Roussel put down to an increase in germ cell production within the animals. He found that in some way the thyroidal activity was altered which indirectly affected semen quality and other metabolic functions. By altering the natural circadian rhythm of day and night, biological and physiology changes occured.

Further Research includes;

Some Effects of The Photoperiod on Development of the Impatiens Balsamea – J. Perry Austin

Prepartum Photoperiod Effect on Milk Yield and Composition in Dairy Cows – Y. Aharoni, A. Brosh, and E. Ezrat

Effects of Artificial Ultraviolet Light Exposure on Reproductive Success of the Female Panther Chameleon (Furcifer pardalis) in Captivity – G. W. Ferguson, W. H. Gehrmann, T.C. Chen, E.S. Dierenfield, and M.F. Holick

Extraretinal Photoreception during the Gonadal Photorefractory Period in the Golden-crowned Sparrow
– Fred W. Turek (below)

Abstract:

Extraretinal photoreception is involved in the perception of light used to measure photoperiodic time during the initiation of gonadal growth in a number of birds. Evidence is presented which demonstrates that extraretinal photoreeeptors are also involved in measuring photoperiodic time during the gonadal photorefractory period in the golden- crowned sparrow (Fig. 3). Untreated sparrows were able to terminate the refractory condition while being exposed to long dim days (16DL:8D; DL–~0.2 lux). However, birds which had their head feathers clipped to allow more light to penetrate through to the brain were main- rained in the refractory state under the same lighting conditions. These results demonstrate that extraretinal photoreception is involved in the maintenance of photorefractoriness in birds.

It has been suggested that the eyes and extraretinal photoreceptors may both be involved in the initiation of gonadal growth in golden-crowned sparrows (Gwinner et al., 1971). This conclusion was based on the observation that a reduced rate of gonadal growth occurred in sparrows with shielded brains as compared to unshielded controls when both groups of birds were exposed to the same light treatment (i.e. 16L:8D; L=6 lux). The results presented here suggest that at a light intensity of 6 lux, light may have been reaching extraretinal photoreceptors even in birds with shielded brains. Therefore, the eyes may not be involved in testicular recrudescence in this species.

This level of research into the effects of prolonged artificial light is increasing dramatically within our current medical health care system as new developments reveal the dangers of disrupting cyclical photoperiodism. It is this biological approach to photoreception in living organisms that my film will attempt to question and explore.

http://www.photobiology.info/