Image Overlay on Architects Drawing

[KarbonBird]

Anyone done any of this sort of work?

If so, what is the process?

Do you superimpose the AP image over the architects CAD drawing, or the CAD on the AP image? How do you highlight the actual work done?

Sounds quite tricky but maybe there is a scientific way to do it??

[MarkWebber]

I saw pics by a guy in Germany that did something similar. His partner would overlay CAD images on the aerial. Getting the perspective right would be the hardest part IMO.

[trireme]

I saw pics by a guy in Germany that did something similar. His partner would overlay CAD images on the aerial. Getting the perspective right would be the hardest part IMO.

Autocad 2007 will let you bring in images. You can mess with the transparency of the layers to get a mix. Mark is spot on, in 3d mode you CAN match the perspective, but it will take you some time. If you dont know CAD, it will take you forever.

[LoopBaCK]

This isn't too hard to accomplish in Photoshop using layers. The aerial image is usually on the bottom then import the overlay drawing on top, adjust opacity down and use the transform tools to distort and adjust until it fits the underlying image. Once it fits you can play with opacity until it all looks good!

Additionally you can further use layers to highlight particular details.

[trireme]

You cant export from autocad the drawing without a background. It would be an image with colored (black or white) background, which you would then be forced to add it to your image, or manual key out the background.

[architorture]

you can export a vector based line drawing with no background from autocad by printing to a postscript level 2 file.

[Neil_J]

The technique is called Photogrammetry (http://en.wikipedia.org/wiki/Photogrammetry). There are several programs for sale out there that will stitch photographs together into a 3d model... I've never used any of them, so I can't say a whole lot about them :o

Here's an interesting website that mapped a college campus back in 1997, using aerial kite photography: http://www.debevec.org/Campanile/ Download the movie, it's pretty remarkable.

[trireme]

you can export a vector based line drawing with no background from autocad by printing to a postscript level 2 file.

Great to know!

[KarbonBird]

This is great feedback - Thanks Neil_J ... BTW do you know the name of any of the software they use to achieve the final product?

[Neil_J]

This is great feedback - Thanks Neil_J ... BTW do you know the name of any of the software they use to achieve the final product?

They used a program called Façade. Here's a good webpage explaining how it works: http://www.debevec.org/Research/

Unfortunatly, they got bought out by Adobe, Inc. which shut down the whole operation. So you can't buy the program, and if you could find it on Ebay, you're on your own, as there's no support for it.

I don't think there are any other low-priced packages out there that do the same thing (I've looked), as most of them cost thousands, or aren't available at all. If anyone does find one though, report back here with details :)

[KarbonBird]

They used a program called Façade. Here's a good webpage explaining how it works: http://www.debevec.org/Research/

Unfortunatly, they got bought out by Adobe, Inc. which shut down the whole operation. So you can't buy the program, and if you could find it on Ebay, you're on your own, as there's no support for it.

I don't think there are any other low-priced packages out there that do the same thing (I've looked), as most of them cost thousands, or aren't available at all. If anyone does find one though, report back here with details :)

Just Googled and found two other packages:

PhotoModeller and iWitness

They look quite complicated to operate...

I'm really only wanting to get an artists drawing - overlaid on an aerial photo.

I have not been able to get the opacity light enough to see the background AP clearly enough - is there perhaps a process for doing this?

[Neil_J]

Just Googled and found two other packages:

PhotoModeller and iWitness

They look quite complicated to operate...

I'm really only wanting to get an artists drawing - overlaid on an aerial photo.

I have not been able to get the opacity light enough to see the background AP clearly enough - is there perhaps a process for doing this?

iWitness is more of a measurement tool, I don't believe it can reconstruct images into a composite. All it does is collect a 3d matrix of points for CAD output... mostly used for accident reconstruction and forensics.

Photomodeller on the other hand looks pretty nice :) Kind of pricey at $1000 but I'm sure if one's business required it, it would pay for itself many times over.

[Neil_J]

I'm really only wanting to get an artists drawing - overlaid on an aerial photo.

Have you looked at Google Sketchup?? You'd have to model the building from measurements , but from there you could skin the building with textures, and put your aerial photo underneath it. From there, you can also throw the whole thing into Google Earth, which your customers might like :)

http://earth.google.it/userguide/v4/images/att_park.jpg

http://sketchup.google.com/

[Griffo]

I've been doing photomontages with Sketchup for a while now. They really look the goods when used in conjucdtion with low altitude aerial photos.

I create the 3d models in sketchup and then merge with layers in Photoshop. The hardest part is getting the angle and FOV right.