From the Survey to the 3D Animation: The Santa Maria in Solario Chapel in Brescia(ltaly)
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Vertice
X (meters)
Y (meters)
Z (meters)
q.m.d X (mm)
q.m.d Y (mm)
q.m.d Z (mm)
1
100,000
100,000
100,000
0,0
0,0
0,0
2
100,000
105,714
100,046
0,0
0,5
0,1
3
105,487
105,331
100,053
0,5
0,5
0,1
4
105,468
99,887
100,007
0,5
0,1
0,1
Table 1: Vertexes coordinate and relative quadratic middle discard (q.m.d)
2.2 Geometries Survey
Because of the articulated architectural composition of the place, the survey of the geometries was made using an orderly and rational
method considering each time surfaces well definite. Therefore the chapel was decomposed in the four sides walls, in the four plumes
and in the dome, associating each ones to a different denomination to allow an easy identification. Particulary to the wall west,
disposed along the side 1-2 of the net, has been assigned the name of "WALL 1," naming the other walls in an increasing way in a
clockwise direction.Following the same criterion the plumes have been numbered, to which were assigned the indexes of the two
adjacent walls as the first two identified figures.
Because of the many measured points, the demand has risen of assign a number of identification to each. The numeration was made
to allow to bring back, immediately and with univocity, each point to the respective architectural element.This procedure was
adopted also in the following phase dedicated to the survey of the control points used during the photogrammetric process.For these
points a different code of identification has been adopted so to easily realize their difference as regards the previous ones. Following
two images describe two different numerations. The # characters symbolize the progressive number code of point.
Figure 4: Numeration of control points
2.3 Wireframe Model Construction
The points coordinates, fixed in the used reference system, were imported in the Autocad software where, using of the spiline
command, has been possible to build a three-dimensional wireframe model of the whole local.
This operation, was conduced verifying the exact reconstruction of the geometries as soon as comparing them with the drafts traced
during the survey. Because of the presence of a jut out cornice, in the lower part of tambour of the dome wasn’t possible to collimate
meaningful points. This and other hidden parts from the cone of shade of the element in projection, were therefore rebuild through a
geometric approximation, legitimated from the limited uncertainty.
The following step, always through the Autocad software, was the construction of the surfaces that have allowed to complete the
reconstruction from a vectorial point of view and for about geometries of the model. The model used for the surfaces, has called
“COON SURFACES” and has characterized from a rectangular meshes that has given proof to approximate in the best way the real
surface. Despite that each wall was fragmentized in more portions, so to reduce the approximation and to make the digital
reconstruction as near as possible to the real course. This wish is perceivable above all in the reconstruction detailed of frames and
pilaster strips.
A particular attention was required from the modeling of the semispheric dome that positioned itself on the four walls according to an
octagonal base. To limit the approximation of the reconstruction within acceptable limits, the surface of the semispheric dome has
been divided in 49 parts. That has been possible also thanks to the elevated number of points, around 600, localized in according to
the stars painted on the dome that describes approximately the meridians.