so I installed Blender a few days ago, and after playing around and getting used to the basic controls and shapes, I decided that it would help to use references pictures of houses and stuff like that, but it was really hard for me to match my camera with the image and my cubes ended anywhere but where they were supposed to be, and that's how I discovered BLAM. I thought it would be really helpful so I installed it, but after an hour I still cannot decipher how does it works. The original tutorial video is really old, and I don't get how to use it, can any of you help me a little bit with this?
Blam has been updated a bit since those tutorials.
Use the MCE (Movie Clip Editor) or Stabilizer, to load the clip. The Blam addon should appear in the Tools panel in a tab called Miscellaneous. Turn on the Grease Pencil in the Properties panel and add 2 layers. Set the color if you want to tell them apart.
To draw a straight line with GP press Ctrl + D key, then click and drag, while dragging release the Ctrl key but KEEP pressing the D key until you finish. I find that zooming the image up is useful. It allows you to trace the line in the image better.
Remember to have your camera selected and preferable have the image active as a background in the 3D view. Then press the Calibrate Active Camera button in Blam.
The background image is only meant for modelling and placement assistance, you will still have to composite the model onto the shot. You can either use a texture projection (from the camera) onto a plane or model, or use the compositor.
Also I made a tutorial on my YT channel about this a little while ago.https://www.youtube.com/watch?v=km7ko2yddx8