Is there a method to scan hand a drawn plan to PDF and keep the scale correct(as per the original hand drawn scale). I noticed that scanned full size drawings are losing their initial scale (a little off compare to original drawings) . I usually scale drawings in AutoCAD model space, this time i just need to create a duplicate of the hand drawn plan. Any help and advise would be greatly appreciated for this workflow.
Always happened, everywhere I worked. I suppose the scans could be off by 1/256" but at that point it's not noticeable with line thicknesses when scaling.
"A little off" is un-fixable, it's the way scanners work, they distort the image because the paper is moving and not always at the same speed/direction - if you scale one axis correctly, the other will be off.
Oh I know that paper will shrink and expand. Just like I know that a properly calibrated scanner won't be off enough to make a difference. Sure the scan may be off a wee bit - no more that the margin of error that line weights create. Hence why you don't scale drawings.
Seriously, how hard can this be? Alternatively, scan it, bring it into Photoshop / AutoCAD / Revit/ sketchup / anything that allows you to resize a drawing. Then print. This is assuming the scale is actually off in the first place. I think copiers might resize things slightly but not scanners. Flatbed would be best.
Yes, flatbed is the best thing to use. It is possible for automatic feeders and rollers to stretch a scanned image, albeit slightly. You can find it discussed on manufacturer support sites for Canon, HP, etc.
Hand drawn plan scanned PDF file scale is incorrect
Hello,
Is there a method to scan hand a drawn plan to PDF and keep the scale correct(as per the original hand drawn scale). I noticed that scanned full size drawings are losing their initial scale (a little off compare to original drawings) . I usually scale drawings in AutoCAD model space, this time i just need to create a duplicate of the hand drawn plan. Any help and advise would be greatly appreciated for this workflow.
WTF are you talking about?
Is my question too confusing for you?
your scanner/software/PC setup must be messed up somewhere, it should be scanning exact.
never happened, nowhere.
Always happened, everywhere I worked. I suppose the scans could be off by 1/256" but at that point it's not noticeable with line thicknesses when scaling.
Hence why you don't scale drawings. :)
"A little off" is un-fixable, it's the way scanners work, they distort the image because the paper is moving and not always at the same speed/direction - if you scale one axis correctly, the other will be off.
Odd. I've never had an issue with scanners like this. Guess ours have always been calibrated correctly.
I guess you also don't believe paper has shrinkage and expansion depending on humidity and temp. go scan a 30 yr old set of plans and let me know.
Oh I know that paper will shrink and expand. Just like I know that a properly calibrated scanner won't be off enough to make a difference. Sure the scan may be off a wee bit - no more that the margin of error that line weights create. Hence why you don't scale drawings.
Fortunately, scale and dimensions are just estimates anyway.
Funny how we always tell contractors not to scale the drawings, then don't listen to our own advice...
The trick is to scan your scale. Then print it out and use it to measure the PDF.
Seriously, how hard can this be? Alternatively, scan it, bring it into Photoshop / AutoCAD / Revit/ sketchup / anything that allows you to resize a drawing. Then print. This is assuming the scale is actually off in the first place. I think copiers might resize things slightly but not scanners. Flatbed would be best.
Yes, flatbed is the best thing to use. It is possible for automatic feeders and rollers to stretch a scanned image, albeit slightly. You can find it discussed on manufacturer support sites for Canon, HP, etc.
just import the image into cad, do a ref scale, plot to paper size, and print…
This. Just draw a graphic scale on your sketch first.
Just scan the drawing with a banana at the same time. That way you can always know the scale.
or a ruler, or am I just being too obvious!
or better yet a banana with a hand drawn scale on it! Sharpies work great!
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