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reinhardtjh  
#1 Posted : Wednesday, October 31, 2007 7:31:25 AM(UTC)
reinhardtjh

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Joined: 5/25/2007(UTC)
Posts: 17
United States

Hi,

Although I had 3 years of drafting in high school (too many years ago to comfortably mention), I'm new to the CAD/CAM world. As a model railroading enthusiast, I'm attempting to convert a 3-view drawing of a diesel locomotive to a 3d solid model. I've got a scanned imaged of the drawing converted to various formats (BMP, PICT, JPG) and I've been trying to trace the imported image, but it's not going real well. So the question is, does anyone have any tips for doing something like this, or know of any web pages that have a tutorial or anyplace that has more hint on ways to try this?

Thanks for your help.

John H. Reinhardt

P.S.

If it makes any difference I'm using VIAcad 2d/3d on a MacPro and OS X 10.4
Art  
#2 Posted : Wednesday, October 31, 2007 7:47:38 AM(UTC)
Art

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The files you have are made from dots, not lines. The best you could do is use them as a background in Illustrator, trace, and import that way. This is what I do for logos and such but not for models. I decided years ago that it was quicker and easier to reconstruct from dimensions. If you have dims on the model, go from scratch. If you don't, use illustrator to either import or determine dimensions and then start from scratch.

Sorry to tell you this, but I have found modeling to be much faster than noodling around with file formats and such. You could even copy the drawings on to graph paper. (how 20th century!)

Good Luck,

Art
dexter  
#3 Posted : Wednesday, October 31, 2007 7:56:17 AM(UTC)
dexter

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Joined: 2/19/2007(UTC)
Posts: 128

Although, it would be very nice to have 'sketch planes', or backgrounds that could be placed and traced in 3D. It works very nice in some other modeling programs, whether you are taking your loose sketches into CAD, or taking elevation drawings and visualizing.
jol  
#4 Posted : Wednesday, October 31, 2007 8:35:33 AM(UTC)
jol

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John

Illustrator CS3 can give you vector lines from a jpg

You'd still have to tweak the lines - possibly even redraw many of them .. but the process may be easier if you have auto-vectorised for a guide

(or has Art tried this?)

Jol
reinhardtjh  
#5 Posted : Wednesday, October 31, 2007 10:06:30 PM(UTC)
reinhardtjh

Rank: Junior Member

Joined: 5/25/2007(UTC)
Posts: 17
United States

My most recent attempt was to import the bmp and then create a new layer on top of it and trace the drawing. What this gave me was basically a 2d drawing. Unfortunately going to the 3d model from that is the hard part. ;)

It looks like Art's suggestion might be the best for me. I have a scale drawing and I can get any dimension from it I need so I guess I'll just build a 3d model that way.

I'm just a hobbyist so springing for the latest Illustrator is a bit beyond my price range. I used to have a copy of it back around V6 or V7 but I don't think Adobe will let me upgrade from that!

Thanks for your help, guys.

John H. Reinhardt
jol  
#6 Posted : Thursday, November 1, 2007 5:56:04 AM(UTC)
jol

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John I will try vectorising your drawing for you if that'd help .. I wasn't suggesting you rush out for a copy : )
reinhardtjh  
#7 Posted : Wednesday, November 7, 2007 4:46:37 PM(UTC)
reinhardtjh

Rank: Junior Member

Joined: 5/25/2007(UTC)
Posts: 17
United States

jol wrote:
John I will try vectorising your drawing for you if that'd help .. I wasn't suggesting you rush out for a copy : )


Jol,

Thanks for the offer. This is all a learning experience with no hard deadlines so I'll keep plugging away as I have time. If it gets to the point where I'm totally frustrated I might take you up on your offer.

John
posh.de  
#8 Posted : Thursday, November 8, 2007 4:32:55 AM(UTC)
posh.de

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if yo can get hold of a Windoze system you might give WinTopo a try which you can get in a functional limited freeware version from here:

http://www.wintopo.com/

you should be aware of the drawbacks of raster vectorization, i.e. entities are approximated by parsing to almost a bunch of lines/arcs and geometric properties as e.g. horizontal/vertical are regularly not recreated.

I have found that correcting the flaws mentioned above is often more time consuming and error-prone than doing a 'clean' design from scratch.

Norbert
POSH GmbH
www.posh.de
jlm  
#9 Posted : Thursday, November 8, 2007 4:57:35 AM(UTC)
jlm

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posh.de wrote:
I have found that correcting the flaws mentioned above is often more time consuming and error-prone than doing a 'clean' design from scratch.
Norbert


I agree 100% with Norbert.
Any vectorization leads to a nasty, bumpy, asymmetric approximation.
I tried almost everything to collect data from existing object or document: tablet, scanner, laser, shadowgraph, video-microscope...
They are only tools to collect information (dimensions and geometry).
Clean construction can only be achieved by clever designer...

JL
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