mstg007 Posted July 30, 2018 Share Posted July 30, 2018 What Could I use to get measurements from existing photos (jpgs)? If I take a photo of a house where I can see the front and side of it. How can I get the length and width of the house? (with a known height of an object already in the photo)? Sorry it I confused you if I did. Thanks! Quote Link to comment Share on other sites More sharing options...
Dana W Posted July 30, 2018 Share Posted July 30, 2018 It doesn't really work at all, especially knowing only one distance. Every single line in a photo is foreshortened due to perspective. Even if you were to scale the photo by reference using the known object, that would be the only distance that would be at 1:1 scale, and ONLY that distance, at that one single location. The variance from scale increases by a negative number (gets shorter) for everything that is further away from the camera than the referenced object, and increases by a positive number (gets longer) for everything that is closer to the camera than the referenced object. Nothing, repeat nothing, in a photo can be considered parallel with the camera viewing plane. Lets say the known distance is the height of one porch post. Only the one single point on the porch post that was exactly perpendicular to the camera lens center point is accurate. Everything in all directions from that point is not at the same scale ratio as that point, and points aren't very large at all. This problem is made worse by camera lenses not having the same focal length. Each different focal length has its own perspective. This is why nobody can say how tall Bigfoot really is. Quote Link to comment Share on other sites More sharing options...
lrm Posted July 31, 2018 Share Posted July 31, 2018 You could try using the feature of 3ds Max. Once you have the camera location you can create a boxes to represent the basic shape of the house and manipulate it to fit the scene. Since you know one of the real dimensions you can use that to appropriately scale the other dimensions of the boxes. Quote Link to comment Share on other sites More sharing options...
SLW210 Posted July 31, 2018 Share Posted July 31, 2018 Similar has been discussed. See these threads. http://www.cadtutor.net/forum/showthread.php?101827-back-to-picture-to-cad http://www.cadtutor.net/forum/showthread.php?101760-picture-to-2d-dwg Quote Link to comment Share on other sites More sharing options...
mstg007 Posted July 31, 2018 Author Share Posted July 31, 2018 Thank you for all the input guys. Thought I ask. Quote Link to comment Share on other sites More sharing options...
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