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C Mansell

Drawing off photographs

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Hi Guys,

I know it's not directly to do with Vectorworks but I'm trying to find a piece of (hopefully cheap) software (preferably mac) to allow me to "straighten up" elevation photographs so I can import them into Vectorworks and then simply draw over them to create accurate as existing elevation drawings.

I don't need absolute pin point accuracy as I would always site measure key dimensions but if I could fix a photograph so it could sit within an accurately drawn outline frame in Vectorworks so I could trace over, say, second floor windows that I can't physically measure on site, that would be excellent.

I have seen that accurate drawing over photographs can be done in a program called Highdesign but from what I can see you need to actually draft in the program, rather than just fix the image and export it elsewhere. I have also seen that sketchup has a sort of photo trace ability but I don't really want a 3d model, just a flat 2d elevation image.

Anyone got any suggestions for a suitable companion to Vectorworks to make this possible?

Cheers

CM

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Photoshop will allow you to skew the perspective (I assume Photoshop Elements will as well).

SketchUp Pro will let you import a photograph and generate a reasonably accurate model from it. Not sure if this is available in the free version though.

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Graphic Converter has all the power you need and a nifty line tool which will straighten the image at any angle. It's a great app ...highly recommend this ... VERY COST EFFECTIVE !

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Graphic Converter has all the power you need and a nifty line tool which will straighten the image at any angle. It's a great app ...highly recommend this ... VERY COST EFFECTIVE !

Seconded.

However, correcting the perspective is a bit tricky with any program; compensating for the projection even more so. For a quite big urban design project I had to write a scaling script that used the frontage (from the cadastral base) to scale the (perspective-corrected) photos to the (approximate) actual width & height. Then one needed to create a 3D-poly and a texture using the photo... Shockingly tedious, if I may say so, but in the end, we were driving by the photo shoots.

This being 19th C & early 20th C Australia and a "commercial & entertainment precinct" of Melbourne, we had also verandahs (canopies) and set-backs adding to the tediousness.

(Dimensionally) true 3D models - there must be a better way! Whatever the software costs, buy it!

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Then one needed to create a 3D-poly and a texture using the photo... Shockingly tedious, if I may say so

Petri, maybe creating an image prop (non-rotating) would be easier. It is usually the quickest way of making a textured 3D polygon, assuming you wanted a rectangle. It would probably be easier to manipulate the mask image than to trace the silhouette using the polygon tools, if you wanted a "cutout" effect.

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Maybe, maybe not. Especially considering the said canopies (over footpaths) that were a major (i) issue and (ii) PItA. Even more so than the Victorian parapets (speaking of a cutout effect).

Anyway, we did not have image props back then...

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Thank you all for your advice. I knew someone in this forum would have the answer.

From what I can see it looks like double take combined with photo match in Sketchup 6 could be the answer I am looking for.

When I get a chance over the next couple of days I'll download the demos and see how they work together.

I'll let you know how I get on!

Thanks again

CM

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Another thing not mentioned is how the photo is taken. You have use a good lens, and be very careful of your position when you shoot. Most lenses and specially on chap cameras and on zooms put on widest angle can distort the picture quite much so that all straight lines become arches like the edge of a full pillow.

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I forgot to mention: a part of my system was a PIO to record the location of the shoot. It made some of the necessary calculations for calculating the width/height ratio. Now, if I had also used a clinometre (hypsometre) to record the tilt angle & otherwise recorded the focal lenght, I would have had more accurate results.

Later on I wrote a PIO just for measuring building heights, based on the clinometer reading and horizontal distance, measured with a cheap (?) laser unit (a golf player's device - closest to playing golf I've ever been!) The things we do...

I can definitely recommend the now available automatic/semiautomatic photogrammetric programs!

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If you're shooting digital, the EXIF data in the photo records such info as the focal length - which you then can type into DoubleTake to correct the spherical distortion = straight lines.

Somewhat offtopic- but some great freeware context menu tools for utilizing EXIF data (Mac only) can be found here: Pixture Studio.

Along with displaying the EXIF data, 'PhotoTool CM' lets you batch rename multiple JPEG photo image files using their EXIF date. Much better than the standard 'IMG_5613' photo name.

Tim

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May be this will do? On Mac OS the installation seems to be demanding on some programming knowledge. I do not get my installation to work. I have not, but will try this via Parrallells.

Another one for windows I neither have tried is

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