The film's second sequence shows a time-lapse day of light
over the modern Parthenon.
The shots progress through the day from sunrise to sunset overlooking
the Caryatid porch of the Erechtheion
The opening sunrise is actually the sun setting over the Pacific shot from the roof of USC ICT in Marina del Rey, California, shown in reverse. This is the only shot in the film not to feature computer graphics elements. It was shot with a time lapse shutter release a Canon D60 digital camera using a 200mm lens, cropping in significantly.
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Shot
8: Timelapse Parthenon
The central shot of the film is a time-lapse sunrise over a wide view of the Parthenon. This shot was created using computer graphics; the model is derived from laser scans and digital photography and the illumination is virtually simulated using the Arnold global illumination system. The Parthenon is currently undergoing an extensive long-term restoration project and is open every day to the public. Rendering this sequence virtually allowed us to show the Parthenon without scaffolding or tourists and to design the camera moves and lighting in postproduction. Shot 8 is a wide establishing shot of the Parthenon shown as a timelapse from approximately 7am to noon.
 Scanned model of the Parthenon:To accurately capture the Parthenon geometry, the Parthenon was scanned over a period of five days using a Quantapoint time-of-flight laser range scanner in April 2003. Fifty-three panoramic scans were aligned and assembled using the MeshAlign 2.0 software from CNR Pisa. To remove the scaffolding and subsequent holes, the geometry was post-processed using GSI’s GSI Studio software, producing a 90-million polygon model of the temple and a 300,000 polygon model of the surrounding terrain.
 How the sky was captured:
While light-probes were recorded in Athens, for rendering we required higher resolution continuous time-lapse sequence. For this sequence, the time-lapse image-based lighting was chosen from one of several
days recorded in Marina del Rey, CA using a new HDR capture process [Stumpfel et al 2004]. These lighting probes was captured using a fisheye lens on a Canon EOS-1ds digital every 40 seconds over the course of a day. This data-set along with more information on this technique is available here (link).
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Shot
9: West Facade of the Parthenon
Two thousand years the Parthenon was a combination of chiselled white marble and brightly painted ornaments. The colors and textures of the Parthenon have changed drastically over the years as the Parthenon surface has been eroded by weather, scorched by fire, and defaced by its changing inhabitants and visitors. As the sun passes overhead we look up at the west facade,. Beneath the lintels we can see the weathered ash from the Parthenon fire along with other discolorations of the marble. In order to create an accurate rendering of the Parthenon under changing time-lapse illumination is was necessary to recover this lighting-independent texture information for the entire west facade.
We solved this problem using a novel inverse global illumination technique (link). By combining simultaneous lighting measurements and photographs of the Parthenon, with the laser-scanned geometry information, we show how to iteratively solve for accurate surface reflectance characteristics.
Inverse global illumination The lighting-independent surface colors of the Parthenon were recovered from digital photographs using a novel environmental reflectometry process (see sketch). This image shows the recovered albedo texture for the west facade.
Lens flare The objective of this shot was to show the sun flaring as it pasted behind the west Parthenon facade. Some flare persisted from the original fisheye lens used to capture the sky. We then added an additional flare as a postprocess filter in HDRShop 2.0. The final filter settings were based on this photograph of an actual lens flare of the sun just behind the Parthenon
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Shot
10: Caryatid Porch of the Erechtheion
Sitting opposite the north side of the Parthenon, is a second smaller temple called the Erechtheion. The most famous section of which is a row of columns carved as female figures called the Caryatids. As the sun sets, we share the Caryatid's view overlooking the Parthenon itself. The timelapse sky shown covers from afternoon to near sunset captured on February 23rd, 2004 in Marina Del Rey.
This shot presented a unique challenge as it combined a wide range of techniques presented elsewhere in the film. The shot combines laser scan geometry of the Parthenon, structured-light scans of the Caryatid cast, and Maya. The Parthenon was assembled and unlit using the techniques described above for shots 9 and 10. During the Athens scanning trip, laser scan measurements were also taken of the Erechtheion itself. These were used to correctly position the Erechtheion in relation to the Parthenon. For details such as the porch roof, geometry was modelled in Maya and textures were hand-painted in Photoshop. The caryatid columns were based on captured geometry from the Basel Sculpturhalle scanning trip (see below) and detail was added to the geometry using a photometric stereo dataset taken in the British Museum as described in a SIGGRAPH 2004 Sketch. To handle the immense geometry load in the scene, it was broken down into multiple elements which were individually setup in Maya, then the final shot was rendered using Arnold.
 Storyboard: As originally conceived this shot would take place during the period of Turkish occupation. However such a shot would require both extensive and rather speculative reconstruction of the village built around the Parthenon at that time.
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Scene setup Later the shot sequence shifted to the present day, and became part of the timelapse sequence. The final framing for this shot was influenced by a similar photograph taken during the Athens scanning trip. This image is shown on the right. |
The caryatid model:
During the Basel scanning trip, we were able to scan their cast of one of the caryatid columns. This caryatid was built as the second column from right on the porch; the original is currently on display in the British Museum in a room outside the Duveen Gallery. The remaining caryatids in Athens have removed to the Acropolis Museum; the ones seen on the current temple are replicas. Our Caryatid model was assembled from multiple scan views using the MeshAlign 2.0 software from the Visual Computing Lab at CNR Pisa. This process is shown in the first image, where each individual scan is color-coded. The second image shows the final untextured model rendered using Arnold.
More information on the Basel sculpture scans can be found in our online sculpture gallery
(link) where this model is available using vrml (link)
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Shot
11: Caryatid Closeup
 Shot 11 shows a closeup of the Caryatid face
as the sun sets in the background. For our early renderings we used
the same geometry as in Shot 10 obtained using structure-light
scanning. However we desired greater resolution particularly around
the face. For this, we used an extension of the photometric stereo
technique first explained in Sequence 1.
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 Storyboard: This shot was one of the first conceived for this film as shown in the following storyboards and renderings.
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 Early rendering of the caryatid face
This shot was first rendered in 2001, with a simple
animated light. The caryatid model was based on only three
structured-light scans, and was not yet complete so there
are still visible holes in the neck.
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Photometric photograph: During a March 2004 trip to the British Museum, we photographed the original caryatid using the flash from multiple directions. This photograph is one of the source images used for recovering geometry of the face using photometric stereo.
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 Recovered geometry
We solved
for the light direction in each image finding the best fit between the
photometric stereo geometry recovered from the original
and the structured-light scan geometry based on the cast.
This additional constraint provided accurate facial detail
that could be combined easily with the original scan of the plaster cast in the Skulpturhalle.
The link on the right contrasts the original structured-light scan geometry with the refined
geometry using structured-light scanning and photometric stereo.
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Recovered albedo With recovered geometry and light directions, we calculated a diffuse albedo map of the caryatid sculpture in London. As each camera produces its own texture view, we generated a set of cohesive UV coordinates using the Graphite texture atlas software (external link). This image shows the texture generated by one camera.
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Continue to 3rd Sequence
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