i tried both the manual method and the “Blam” one. Blam got me very close, but tracing the image then gives me unrealistic architectural measurements, a ceiling height of 6 meters and a depth of 15 meters. and this is not accurate, not even close, to the theoretical measurements for a space like that.
i also attached the original image along with the original camera settings used to take the picture.
I note you have the View Lens set to 35mm and your Canon set to 17mm, but what have you set the Blender camera to?
How have you setup the units in your Blender Project?
How did you set up the “scale” of the reference image?
Do you have any reference dimensions to work with?
How are you expecting to be able to draw to scale from a perspective image, particularly when the image is from a 17mm focal length camera?
Normally for “Tracing” from a reference image you would want the image to be as long a focal length as possible to remove distortion caused by the camera. If you look at Witold’s “Navy Dauntless” WIP you can see how he has coped with image distortion from a camera to achieve accurate dimensions - he has had to use many images, you may need to do the same. Also normally you will need a reference dimension from the image to set the scale you are working to. This becomes obvious if your image is say from a 5 Megapixel camera and you take an identical picture from a 20 Megapixel camera and then load them both as reference images - you will see a difference in the size of the image with regard to Blender units.
I have to say that I would need far more information before I can help further as I am only guessing what the issue might be at the moment.
@JohnAntoineG: the most important thing to begin with is knowing the sensor size of the camera you’ve used. This directly influences the actual behavior of the lens. Canon 5D is a "full frame’ DSLR and its sensor has roughly 36 x 24 mm. You use these values in Camera’s Sensor settings and only then you can set the Lens value correctly. For example, the 17mm lens will produce different results on Canon 70D which has 22.5 x 15mm sensor (the image will be cropped 1.6x times so 17mm lens will actually work as 27mm lens).
i work as a freelance 3d artist using tools other than blender, have been in the business for 3.5 years, doing archviz mainly.
what i was looking for is to understand the possibilities of photo matching in blender. if you be so kind as to check the chocofur tutorial, the guy manages to get the image matched without any plugins, and from a single image. and he also managed to do that with an incorrect focal lens of 22. I know it is incorrect because i developed the habit of examining the metadata of anything i use. and indeed the camera data was provided in the metadata of the image he himself used.
so the workflow i wish to inquire about is the “wingin’ it” approach. that might be useful in some cases like the acquisition of an image from a client with no details and no data, and the client require the change of certain design element.
the concept of photo matching is totally new to me, because the way i usually work as an architect and a 3d artist is that i either design the space myself using sketches , then CAD plans, then finally go to my 3D program of choice. or get an already finished CAD drawings from a professional firm that i then begin to visualize.
i am trying to kill two birds with one stone, learn a little of blender, as i have been trying to do for several years now, but due to little or no free time never succeeding. and learn a new technique as a whole.
this is actually not my first try, but unfortunately i lost the first file. In the past trial, i got everything that you told me about, sensor size, focal lens, resolution, everything except vertical and horizontal shift. and still no luck.
something like blam got me very close, but it uses a focal lengh of 150, which yields the un-realistic dimensions.
If the image isnt cropped matching camera should be straight forward… In camera tab select full frame - sensor type than use focal lenght of 17mm for your lens…than match the camera orientation.
If image is cropped than 17mm focal lenght isnt right anymore but it should be somewhere near.
I would set sensor to full frame than use the same 17 mm for the start.
Determine some object dimesions like ceiling height or window and door dimensions.
Lets say u determined that doors under the stairs on the right are 0.7mX1.6m
make a plane of 0.7mX1.6m and place the plane upright on X axis
Than match the plane with the doors by moving/rotating your camera
In this case i would choose the right side of the table and determine the height…than make a plane of that same dimension and match the camera…the side is in the perspective so you can tweak the focal lenght…
Cmos on canon 5d Mk2 is full frame so focal lenght of this image is 38mm. The ceiling is about 4,5 m high and central counter is about 80 cm high. Thats the closest i could get.
