Graphics Programs Reference
In-Depth Information
SketchUp to import and scale images as textures allowed maps to be imported at
scale; finally, photographs were used to enhance the buildings in the model using
historic photographs that were brought to life via the integrated Match Photo
tools. Most of the modeling was done with the native SketchUp tools.
New Approaches
SketchUp has quite a large user base in the field of architecture; but its use in
modeling historic sites has only begun to be exploited. The ability to match
photographs and use the program for what I call “poor man's” photogramme-
try makes SketchUp a very useful tool for pulling historic photographs into a
three-dimensional model. This is a very powerful tool native to SketchUp and
is frequently underutilized as it is used for little else other than for creating
very simple Match Photo buildings for Google Earth. As detailed in this chap-
ter, this feature can be used for many other advanced applications.
Step 1: First Attempts via Match Photo
Goal
: To provide preliminary explorations of modeling.
Input
: One historic photo of the mill.
Tools
: SketchUp Match Photo.
Photogrammetry is a term used by cartographers, archaeologists, and
architects. It refers to a process in which geometric properties of objects
are determined from photographic images. There are currently many high-
end software packages that make photogrammetric calculations using very
complex formulas based on optics and projective geometry. Although these
programs have a very high degree of accuracy, they are often expensive and
difficult for a layman to use.
The Match Photo feature of SketchUp allows even a novice user to create
reasonably accurate three-dimensional models from photographs. In the case
of historic photographs, one has to make a few inferences about scale and
proportions to get the model as accurate as possible. Before beginning the
modeling process, it is advised that you become acquainted with the architec-
ture of the concerned area and era.
The photo matching process is rather straightforward. First, the image is
brought into a blank workspace using the Camera > Match New Photo menu
items (See Figure 16.1). As shown in this example, the reference photo should
provide a three-quarters view of the building. The Match Photo interface can
be a bit overwhelming at first, but there are three steps that can simplify the
visual confusion:
1.
Set the origin to the corner of the building by dragging the yellow square
to the corner of the building.
2.
Using the green and red alignment guides, align the guides to two
perpendicular faces on the building. In this example, I used window
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