Reliable 1:1 scan software?

[Mechv5]

Hello,

I'm trying to figure out how to scan a sketch at real 1:1 scale, to be able to reproduce the geometrical elements as detailed as possible in a CAD sketcher. For example, if I "copy" the geometrical form of an object (just do the trace of the profile with the pencil on a paper sheet), I would like to be able to scan the profile on the paper at 1:1 scale, in order to sketch it in a CAD sketcher with the highest possible accuracy. Could somebody point me to a good and reliable software which will do the (scan) job with a normal (consumer) scanner?

Thank you very much in advance for your answers!

 

[GregLocock]

Uusally I put a grid onto the sketch so I can correct the scan, if needed.

Cheers

Greg Locock


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[corus]

I usually just manually scale off the drawing if there are real dimensions shown on the drawing. It's strictly taboo though as most drawings will say 'Do not scale off drawing'. Another way is to use a program tracer.exe which you should be able to download off the net. Put in the sketch in jpg format and then scale off points where you know the dimensions.

corus

 

[Mechv5]

Thank you for your answers. The methods described here are unfortunately not precise enough for my task... It is hard for me to believe that there is no software for an accurate 1:1 scanning of a hand-sketch, but it seems that it is like this...

Wish you a good day.

 

[ewh]

"not precise enough" and "hand-sketch" just don't seem to go together well. There have been good suggestions made, but it does require an extra step or two to actually measure in a couple of directions (or use a grid) a feature of your sketch and to then scale the resulting geometry appropriately.
What is it that makes this sketch so precise?

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[IRstuff]

You talk "accuracy" and "precise" yet offer no requirement to rebut the suggestions. You keep referring to scanning "software" but it's the hardware that does the scanning. What exactly are you trying to do? How are you doing the scanning?

TTFN

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[KENAT]

You seem hung up on the accuracy thing but inherently even if tracing round something with a small dia mechanical pencil the material you come to scan isn't particularly accurate.

If you want accurate then something like:

http://www.zcorp.com/documents/112_ZScanner-singsheet-v08.pdf

may be better - or a lot of time in a CMM machine.

Even then, you'll have only measured one unit most likely and don't know how that one varies from the mean...

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[jhardy1]

If you do a Google search for "raster to vector", you will find many options for taking a scan and vectorising it into lines, arcs, etc. Find one that will export dxf and go from there.

Having said that, my own experience is that unless you have a really first-class scan, and a very high quality original image, many of the automatic raster-to-vector software will typically generate output which will need quite a bit of manual cleaning up. (E.g. scanning artifacts will be translated into short lines or vertexes; lines which appear to meet on paper may or may not intersect at a common vertex in the CAD version; etc.) Manually "tracing" a scan in the CAD package of your choice can often be more productive in many cases.

Hope this helps!

 

[TheTick]

It is hard for me to believe that there is no software for an accurate 1:1 scanning of a hand-sketch

If you know more than squat about raster-to-vector conversion, it's a bit easier to believe.

AutoCAD has a really good raster-to-vector conversion tool.

 

[Qshake]

The fact that hand sketches and PAPER are involved in a precision/accuracy requirement is "sketchy".

Paper, afterall, is subject to moisture and thermal changes. Ask anyone who has ever plotted a drawing (scaled) and then went back to the paper plot with a scale.

Regards,
Qshake

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[ewh]

... or had to re-stretch their drawing every morning when working on the board.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]