background image
235
web.Today's desktop computers are enough powerful and network bandwidths sufficient to
successfully render 3D simulations over the Internet.The trick is, to provide multiple 2D
views that are stitched together to simulate a 3D experience. Users can manipulate these
simulated 3D objects, can rotate 360 and tilt them by 90.These simulated environments
can be created at a fraction of time and cost than real 3D. In addition, as only images are
transmitted, the requirement for bandwidth can be considerable reduced, as explained in
the enclosed case study.
The disadvantage of this technique in comparison to real 3D rendering is the limited
navigational possibilities and the fact that the physical form and dimensions of an object
cannot be captured in enough for certain purpose. Real 3D presentation demands an
accurate geometric model of an object in 3 dimensions, plus additional information on
the texture and colour of the various surfaces.
At present, there are two techniques for the creation of 3D models. First, building models
from scratch using particular software, or using a 3D scanner to scan the geometry of an
object using laser range-finding technology and texture mapping.This model is then further
worked on to create a 3D effect by adding light and viewpoints to the 2 dimensional model
before it can be rendered; this step is called ray tracing."Ray tracing is a computationally
intensive process in which the path of every single ray of light is traced from the light
source(s) as it reflects off or refracts through each of the surfaces in the model until it
eventually reaches the viewpoint or camera." (Gill, 2001) The more viewpoints are added,
the more realistic the 3D object or environment, but the longer also the rendering time.To
create a single image can sometimes take days, at exploding costs.That is why very complex
scenes with a high level of realism that is almost indistinguishable from reality such as in
movie special effects are extremely expensive. In addition, objects can be programmed with
particular behaviours that allows users to interact with them, rotate them, tilt them and
navigate around.
With regard to the cultural heritage sector, Gill identifies especially the following areas
where 3D can be especially useful:
3D in archaeology: Archaeologist rely heavily on spatial information for
reconstructing ancient sites. However, as layers and layers of sediments are removed
during excavations the details of a location get lost and the site is actually destroyed.
In this case, 3D in combination with geographical information systems helps to
capture as much spatial information as possible. Hence, it comes as no surprise that
archaeology was one of the first disciplines to embrace 3D technology.
Constructing complex virtual worlds: Reconstructing worlds that are not easily
accessible or that did not exist at all is another area for 3D use in culture.
Reconstructing the objects and their context allows to prove/disprove hypotheses
and theories about those environments.
Online exhibitions in 3 dimensions.
Virtual repatriation: Objects that are dispersed all over the world return to their
original settings and cultures in virtual form.
IX TECHNOLOGY