[WWI] drawing 3-views from photos

[Aidrian Bridgeman-Sutton]

The technique I have used in the past - though not for flying machines -
needs you to reverse the process used to produce measured perspective
drawings; there are several tutorials on this subject on the web but I will
try and help with reversing the process if you get stuck, though text based
email isn't the best way to communicate some of the concepts. 

The best thing you can do is try and draw plan and elevation of a simple
structure like a hanger before trying something complex like a plane; these
have the advantage that the shapes are essentially comprised of triangles
squares and rectangles with a few curves now and again, whereas the typical
aeroplane rarely co-operates by giving you nice right angles and straight
lines to measure 

The hard part is that you need to estimate the vanishing points and that
usually requires a very large drawing board or a really capable CAD program.
Even then you will only get a drawing which corresponds approximately to the
right shape and size for several reasons: - 

- Measured perspective usually considers just two or three principal
dimensions whereas in reality the perspective exists in every direction

- You are going to find that unless you know the exact set up used on the
original photo you will have to estimate the angle of view to set up the
geometry. A small error here can really screw up the final product - couple
that with the distortion inherent in many older cameras and you'll often
just have to interpret based on what you know of the builders practice   

 - Results will usually be better when you have several views taken at
different angles and can combine the inputs from several sets of
measurements  

Aidrian

-----Original Message-----
From: wwi-bounces at wwi-models.org [mailto:wwi-bounces at wwi-models.org] On
Behalf Of iban
Sent: Monday, July 10, 2006 12:46 PM
To: World War I Modeling Mailing List
Subject: [WWI] drawing 3-views from photos

is anyone aware of any instructional material out there on how to draw 
plans in 3 or more views from photos?  i know about the old article in 
wwi aero, but haven't been able to find much else, since.

i'd love to see a really good step-by-step tutorial on the subject.

i'm kicking around the idea of starting an open source drawing 
repository, where folks could post photos, others could take a shot at 
some part of a drawing, everyone could see and verify both the 
underlying work and the sources, and anyone could leave comments on the 
resulting drawings in the same way flickr.com lets people comment on 
details in photos.  i.e. you could highlight the wheel of an albatros on 
the website, type in "this wheel is too large based on this wheel <link> 
in this photo <link>." or whatever.

any thots?  i'm looking for a way to not only harness but preserve the 
collective wisdom of the list in a new and graphical way.

iban. 

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