Cropped pictures need not apply
November 16th, 2007 | Published in Google SketchUp
Posted by Aidan Chopra, Product Evangelist
I received an interesting question from a gentleman in Greece the other day; he was trying to use SketchUp's nifty photo-matching feature to build a model based on this rendered image of a building. Needless to say, he didn't have any luck. To get the photo-matching feature to work, your image needs to be uncropped. That's why lots of renderings, magazine images and pictures from architecture books don't work; they've been re-framed. Why should this matter? It has something to do with re-positioning the center of the image. SketchUp's photo-matching feature works by assuming that the center of your image is also the image's "center of projection" (where the camera was pointing when you took the picture). When you crop an image, you move its center.
There is, of course, an exception to the "No Cropped Pictures" rule when matching a photo: If your picture has been cropped by an even amount on each side, or by an even amount top and bottom, the center of projection is maintained, and thus everything will work just fine.
Update Clarified the exception to the "No Cropped Pictures" rule in the last paragraph.
I received an interesting question from a gentleman in Greece the other day; he was trying to use SketchUp's nifty photo-matching feature to build a model based on this rendered image of a building. Needless to say, he didn't have any luck. To get the photo-matching feature to work, your image needs to be uncropped. That's why lots of renderings, magazine images and pictures from architecture books don't work; they've been re-framed. Why should this matter? It has something to do with re-positioning the center of the image. SketchUp's photo-matching feature works by assuming that the center of your image is also the image's "center of projection" (where the camera was pointing when you took the picture). When you crop an image, you move its center.
There is, of course, an exception to the "No Cropped Pictures" rule when matching a photo: If your picture has been cropped by an even amount on each side, or by an even amount top and bottom, the center of projection is maintained, and thus everything will work just fine.
Update Clarified the exception to the "No Cropped Pictures" rule in the last paragraph.