Mark P

Inserting scanned object

Greetings everyone;

 

I am preparing a set of draughts of the Royal Caroline of 1749,  and I want to include all the carved work.  I intend to draw all the carved work by hand,  using ink and pencil,  and then scan the drawing,  remove the background rectangle,  and import just the carving into CAD.

 

However,  I cannot find any way of permanently removing the unwanted background,  and creating a file with just the outline of the carving and all its detailing.  Everything I have tried,  and I have spent quite a few hours with several programs attempting this,  leaves a white rectangle which blanks out all existing objects around it.

 

Is anyone aware of a method of removing the background rectangle,  leaving just the lines and shading I have drawn.

 

Any help would be much appreciated.

 

I am using AutoCAD LT2016,  and have tried Photoshop elements and Power Point to remove the background.

 

Example file below.

 

All the best,

 

Mark P

post-10197-0-50160400-1476596689_thumb.jpg

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Mark,

 

I don't understand.  If you are redrawing everything in pen and ink and pencil, I assume you will not draw the background rectangle so it will not be there when it is scanned in.   I am definitely missing something here.  Is  your attached one of the carvings from the vessel?  If it is, can you show this carving example in situ on the Caroline?  That may help understand what you are going for.

 

Allan

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Hi Allan;

 

Thank you for your reply.  The attachment is based on a detail from the draught (none of the other carvings are shown on it) 

 

I have drawn it on a sheet of A4 paper,  and when I scan it,  the scan is rectangular in shape.  Even if I drew it on clear film,  the result would be the same,  as a scan will still be rectangular,  and will pick up the white background of the scanner lid. 

 

I attach an example of this imported into the CAD drawing.

 

Thank you for looking at this.

 

All the best,  

 

Mark P

post-10197-0-64935100-1476612354_thumb.jpg

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It would depend on what your image format is from the scanner. With a number of the image editing programs you can set a particular colour to transparent. (Try Gnu Image Manipulation Program, GIMP - I know awful name, but it is a good program). Something like that may be what you are looking for and would work for the bitmap type formats. You'd have to save it in the correct format as well, JPGs don't do transparent, PNG's and BMPs do. If you want a drawing rather than a bitmap try Inkscape. Import from your scanned image and convert to SVG. The drawings of the carvings would then be scalable as well. I think most CAD software should be able to deal with SVG's now.

post-11252-0-78625400-1476613691_thumb.jpg

Hope you don't mind my attempt at a quick example.

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Hi Fatfingers;

 

Many thanks for the post. 

 

I can vary the image format from the scanner,  if I know what type to save it as in advance. 

 

Can you explain the difference between a drawing and a bitmap.  Scaleability is important,  so it sounds as though I need to look at Inkscape. 

 

Thanks again.

 

All the best,

 

Mark P

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Hi Fatfingers;

 

Wow!  I have just seen your alteration to my picture.  I hadn't seen it when I posted the above reply. 

 

That's just what I want to do.  How did you do that?  It's like magic! :)

 

Many thanks,

 

Mark P

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Hi Mark,

 

Bitmap (probably more correctly termed raster formats) image formats represent the image as a fixed grid of pixels with a colour component per pixel, and possibly transparency which is the apha channel. Drawing formats, like CAD formats and SVG (Scalar Vector Graphic), represent the image/drawing as a series of primitives, lines, curves etc. As you scale a bitmap image it will become pixelated, while a drawing will simple redraw, accurately, at larger resolution; zoom in to a CAD drawing as compared to zooming in to a digital photograph.

The example was done in GIMP. There is an option under the color menu item for 'color to alpha'. Using white as the color to treat as alpha/transparency produces that effect. GIMP has it's own file format, so you have to export the image as something like a PNG which will include transparency. JPG will not allow transparency.

Because your carving drawings are black and white (or nearly) Inkscape may be able to do a good conversion from the formats produced by your scanner to SVG, if your scanner doesn't produce SVGs anyway (would depend on how expensive, if it can do things like character recognition for example). There are also online converters but you might have to pay.

Also, JPG format is lossy, that is to say it uses compression that loses detail; whilest PNG is loss less, it uses compression that does not lose detail.

 

Hope I've been of help.

PeteB, trippwj, mtaylor and 1 other like this

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Hi Mark,

 

I've tried a quick conversion to SVG in Inkscape, unfortunately the website won't allow me to upload it as an SVG file. It does work however, and, I think, quite effectively.

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Hi Fatfingers;

 

Many thanks for all your help.  I am very grateful for the trouble you have gone to to answer my query.

 

The explanation of bitmap vs drawing file is very helpful.  I have not used bitmap much,  and I will certainly not for this project.

 

My scanner only gives the option of bitmap, JPEG, PDF or TIFF files.  Will a TIFF be okay to load into Inkscape,  and convert to an SVG file.

 

If not,  then I will have to get a new scanner,  one which offers PNG as an output option.

 

Is conversion to SVG sufficient to create the transparent appearance,  or do I still need to set white to transparent.

 

Once again,  many thanks for your help.

 

All the best,

 

Mark P

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Hi Mark,

 

Tiffs, BMPs or JPEGs should be useable as intermediate formats to use with Inkscape conversion. TIFF's and BMP's can be very big though. There would be no need to set white to transparent. See below, two screen grabs from my very cheap CAD program - it's certainly not AutoCAD. Produced after importing into Inkscape, tracing bitmap (under the Path menu)  and importing into the CAD program. (I have a passing fascination with the HMYRC, you might notice.)

post-11252-0-27666700-1476627203.png

post-11252-0-50319200-1476627206.png

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Hi Fatfingers;

 

Thank you for your patience and the further guidance on how to do this.  I am very happy to learn from you. 

 

I will purchase a copy of Inkscape,  and set to work.

 

I thought I recognised the background in your post!  If you are building a model of Royal Caroline,  then for God's sake talk to me before you go any further,  especially if you are using Sergio Bellabarba's book as a guide (it was his book that piqued my interest in her,  but as soon as I did even a modicum of research,  I realised that his book is riddled with errors.  It is easier to list what he has got right than it is to list what he has got wrong!)

 

Full credit to him though for a beautifully illustrated book.  And research is undoubtedly much easier now than it was.  But some of the errors are so obvious and so easily avoided that it is not easy to remain polite.

 

All the best,

 

Mark P

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Hi Mark.

Thank you. I hope the info is of some use. I've been keeping up with your posts on the ship and I'm looking forward to seeing, and perhaps reading, the results of your researches with great anticipation. 

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Hi Fatfingers;

 

Your help has been invaluable.  Thank you again.

 

I too look forward to reading the results.  But it will be a while yet!

 

All the best,

 

Mark P

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Greetings everyone;

 

Following on from all the help which I received from fatfingers (for which thank you again)  I have found out one thing which may interest fellow-modellers/draughtsmen,  and have a further request for any advice or help.

 

I am now able to insert a raster image in a drawing,  on top of my background layer.  This still has the white rectangle,  but,  if the image has been made transparent by the process outlined above by fatfingers,  it is then possible,  using AutoCAD's own properties menu,  to turn on and off the background transparency of the inserted image.  The white background disappears,  leaving the image clear. 

 

However,  I am still left with the rectangular outline around the inserted object,  and I wonder if any other members have an idea of how to remove this unwelcome survivor.

 

All the best,

 

Mark P

post-10197-0-89286300-1476990863_thumb.jpg

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Greetings everyone;

 

Following on from all the help which I received from fatfingers (for which thank you again)  I have found out one thing which may interest fellow-modellers/draughtsmen,  and have a further request for any advice or help.

 

I am now able to insert a raster image in a drawing,  on top of my background layer.  This still has the white rectangle,  but,  if the image has been made transparent by the process outlined above by fatfingers,  it is then possible,  using AutoCAD's own properties menu,  to turn on and off the background transparency of the inserted image.  The white background disappears,  leaving the image clear. 

 

However,  I am still left with the rectangular outline around the inserted object,  and I wonder if any other members have an idea of how to remove this unwelcome survivor.

 

All the best,

 

Mark P

Hi Mark,

 

I am no expert with CAD, I know just enough to be dangerous...

 

However the red rectangle you are referring to is the color of the layer you used when inserting the image. It may be possible to make that particular layer transparent. Someone who knows CAD better might be able to help with this. I think you said that you are using AutoCAD 2016LT, I use AutoCAD2012 so I am not sure if That feature is available.

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Hi Mark,

I am no expert with CAD, I know just enough to be dangerous...

However the red rectangle you are referring to is the color of the layer you used when inserting the image. It may be possible to make that particular layer transparent. Someone who knows CAD better might be able to help with this. I think you said that you are using AutoCAD 2016LT, I use AutoCAD2012 so I am not sure if That feature is available.

Always ask google first!

 

https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/AutoCAD-Core/files/GUID-B7E62759-B807-4691-86C7-E365C7D2692B-htm.html

 

Have not tested this, but it should work...

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Hi FS;

 

Thanks for your thoughts.  Fatfingers found the solution to this for me,  which is to go to modify, object, image, frame and make the frame's value 0,  which I believe is the equivalent of making them transparent,  as you suggest.  All frames then disappear. Great!

 

All the best,

 

Mark P

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If you do as much as possible in CAD and save that in PNG or 100% JPEG in as many different parts as you need,

the files when opened and compiled as layers in a drawing program like PaintShop Pro or Gimp will do as you wish.

To remove the white background, select it with the wand tool and Cut the selection.  Duplicate the layer before you do

this and work on the copy - in case.  Use CAD as a preliminary tool rather than the main one.

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Hi Jaager;

 

Thanks for your advice.  I understand CAD well (far less well than some who put examples of their work on here though) and know little of graphics programmes (although I really wish I did know far more,  but I have no time to learn) So I need to use a method that allows me to insert objects into CAD drawings.

 

With FatFingers' much appreciated help,  I have found a way to do this.  Thank you to all contributors for their thoughts,  though.  I have received a lot of good advice.

 

All the best,

 

Mark P

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CAD - Computer Aided Design -  I have tended to focus on the design factor after not being able to find a way to

extract frame timber outlines after inputting Waterlines - and Buttock lines.  I think that this would be possible but

time costly using a vertex or NURBS modeling program.  My Ultimate is to use A Deane instructions and recreate

his Royal Charles ~ 1673.  CAD seems to be the way to do that. But I suspect that I would be starting too late to be able to finish.

 

But,  otherwise, I am using existing plans.  Vessels that have already been designed - a long time ago.  I find a drawing

program to be more useful.  I have found a way to avoid having to loft individual frames to do POF.  A drawing program

gets me there and I only use a small fraction of the program tools.  The important part is that it allow large files with a

ton of layers and not crash.  You do not really need to learn more that a limited number of functions.  The bulk of the tools

deal with painting and photo manipulation and color distortion - none of which are relevant to our needs.

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But,  otherwise, I am using existing plans.  Vessels that have already been designed - a long time ago.  I find a drawing

program to be more useful.  I have found a way to avoid having to loft individual frames to do POF.  A drawing program

gets me there and I only use a small fraction of the program tools.  The important part is that it allow large files with a

ton of layers and not crash.  You do not really need to learn more that a limited number of functions.  The bulk of the tools

deal with painting and photo manipulation and color distortion - none of which are relevant to our needs

 

 

Hi Jaager - I'm in Mark Ps league if you have the time I would appreciate a brief summary of what you use and how you use it? - Cheers Pete

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