Figure 1: Part of the palais with some photo positions
Evaluation of the image material was performed with
the RolleiMetric MR2 software package. Measure-
ments were taken on a digitizer in eight times enlarged
prints. Standard deviation of the image measurement
was given with 0.015 mm after the bundle adjustment.
Accuracy of orientation points in the object is 0.01 m.
Architectural details were taken from a minimum of
three photos. The measured values like points and
polylines were converted into Intergraph's Microsta-
tion. A complete set of two-dimensional facade dra-
wing were evaluated .
3D-SURFACE-MODELLING
Based on 3D photogrammetric measurement results
and the 2D drawings, produced within Intregraph's
microstation, a 3D surface model was produced with
the AutoCAD release 12 drawing editor.
At the outset a very roughly 3D model was generated
by using the ground plane and the facade drawings as
flat walls. From this first model the final complete 3D-
model was derived with special considerations of layer
definitions.
Separation was done according to materials. For
example a window is separated into glas, wood and
stone material. Furthermore some special details like
ornamenmts of the masonry were designed in layers.
174
The complete model had a size of 5 Mbytes. By clea-
ning the drawing from unused references the size of
the drawing reduced to a useful amount of 3.5 Mbytes.
For efficient data handling the CAD system enables
the user to work with external refernces.The content of
external drawing parts is ownly shown but not loaded
into the drawing itself. That is different from inserting
blocks. Moreover changes made in the referenced
drawings are automatically updated in the current
drawing. Therefore any drawing including XREF's is
available in the latest version.
Referenced Layers, block definititions, line, text and
dimensions styles are named dependent symbols. Is a
drawing loaded as an XREF, an access to those
dependent symbols is impossible. Thus layers only
existing in the referenced drawing can not declared as
current layer. One consequently can not draw on such
layers. However depending symbols can be linked into
the main drawing for allowing access to them.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996
Figure 2
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