Subject: NAC- cad design question

[superba]

Hi,

I've been watching this thread like my cat watches birds.  Steve's
explanation is correct about vector vs bitmap, but a *.jpg type file can
sometimes be enlarged without losing clarity.  Adobe Photoshop has a
function that allows a small *.jpg file to be enlarged with an option to
"reprocess" it to maintain resolution.  I've never tried it, but it's there.

Someone asked:  "What are you trying to do?"  There are a myriad of CAD and
graphics products and it's hard to get a general rule to apply.  However,
specific products have specific functions that work with individual
products.  For example, I have some Autocad drawings from yesteryear, and,
once in a great while, I want to manipulate one of them.  I can import them
into Visio and do just that.  However, I doubt that would hold true across
the board.

My .02.

Cheers!

Jim Jordan

>  Message: 9
>  Date: Wed, 04 Feb 2004 10:49:35 -0500
>  From: SJ <syljay at optonline.net>
>  Subject: Re: Subject: NAC- cad design question
>  To: quattro at audifans.com
>  Message-ID: <000b01c3eb36$7d2f5080$b615c444 at dell450>
>  Content-Type: text/plain; charset=iso-8859-1
>
>  Steve
>  My understanding is that Cad type files are based on mathematical
>  expressions. A line is represented by a vector . . a starting
>  point with a
>  known distance and direction.
>
>  The reason for this is that you can enlarge the drawing to any
>  size you want
>  and you lose no clarity. If a line is expressed as 2 units
>  starting at x,y,z
>  and at 270 degrees, and you enlarge the pix by 2x, the line
>  becomes 4 units,
>  270 deg, 2x, 2y, 2z etc etc etc.
>
>  Once you convert the cad file into a jpg file, you lose all those math
>  expressions. The jpg format only understands pixel positions, colors, and
>  how many repetitions(compression) of that before a change is
>  made. When you
>  enlarge a jpg pix . . . .you dont get more pixels added to make the pix
>  sharper. The original pixels just get enlarged.
>
>  You cannot convert pixel locations and colors(jpg) back into mathematical
>  expressions(CAD).
>
>  I think thats how it works, more or less.
>
>  SJ
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