Conference vmszoo::rc

    I have increased woodworking plans using a copy machine without any
    distortion.  I really depends on the detail and how large your going to
    blow this up.   

>    Does anyone have any experience with simply Xeroxing the plans? Does it
>    distord the plan in any way? 

Xerox machines distort somewhat. I guess it depends on the quality of
the machine your using. Yes?

Has anyone tried scanning plans into a computer? Your scaling would be
quite accurate then. Although you'll probably get some distortion there
too just from the scanning and printing processes.

The only difference between the two processes is that the xerox uses a
lens to enlarge, and the computer would use an algorithm to enlarge.

Dave

Copiers (at least in the USA) have a built in distortion factor to foil attempts
at copying money. I read about it once and it isn't uniform. I have played
around with scanning plans (to get airfoils to cut cores) and the success
depends on your scanner. ALWAYS compare your measurements before and after
enlargement. I have had my best luck scanning in "lineart" mode rather than
bitmap mode and then taking the image and "tracing" the parts I want to get
smooth lines. It helps if you have a straight line on the image so you can
remove the skew (most scanner software has features to paste strips together and
deskew the images)

Once you have a 2D wireframe, enlargement is easy.

The other problem I've seen with copiers is that the line WIDTH is also
enlarged. I had a customer that did it from magazine planes and the final copy
he sent me had 1/4" (6mm) wide lines. Where do you cut?

    I have tried 5 methods so far:
    
    1) Photocopier: Enlarge the plan by section, using the features of the
    drawing to puzzle it back together. This thecnic takes time and
    patience. It will distort the plan somewhat but you can usually correct
    them by hand after. If you want to do a real scale airplane it may take
    you several hours to get it with the accuracy you want.
    
    2) Projection: Make a copy of the plans on a transparency and project it
    on the wall on a bigger size paper sheet at the scale you want, and
    retrace. This thecnics take as much time as (1) but you eliminate
    distorsion due to putting back several pieces together. You still get
    distorsion due to lenses.
    
    3) Measure original, redraw using CAD encrease scale and print. This
    thecnic also takes lots of time but is more accurate then 1 or 2. as
    long as your measuring methods and device are accurate.
    
    4) Scan plans using a scanner and transfer the file into a CAD system
    where it can be changed and printed to a larger scale. This is by far
    the most rapid thecnic, but you still get distorsion from the scanner
    lense.
    
    5) Get it done by professional. The most rapid but cost $
    Also the most accurate.
    
    If your handy with your hand you can make yourself one of those
    enlarger machine that look like a parallelogram. If done well they are
    quit accurate and fast to use.
    
    Jacques

    Re: .4
    
    >If your handy with your hand you can make yourself one of those
    >enlarger machine that look like a parallelogram. If done well they are
    >quit accurate and fast to use.
    
    Jacques,
    
    I guess these are called "pantographs"? Does anybody know how these
    work / how to build one / where to get plans for that?
    
    Naief

    The larger art supply stores carry them (not sure where you're located)
    
    Jim