The Disney+ Marvel Studios' series: Secret Invasion contains an amazing sequence set in Red Square in Russia, but they actually filmed this in Halifax, UK. The location they used is the Piece Hall, an 18th century listed building, and the series creators wanted to add an extra floor and dome to it. Seeing as I live less than an hour from Halifax, I visited one morning and shot my own footage to see if I could use digital setting extensions to recreate the look.
I tried out CamTrackAR and got some good results, but messed up during recording so instead I used After Effect's built-in Camera Tracker and was really happy with the results.
In this video, I go through my process, explaining how to use Camera Tracker and how to take still elements from the video and either use directly or import into Photoshop to create the digital set extensions and then place them in 3D space.
Once the tracking and placement is done, I go on to describe how I disguised that effect by placing other items in the scene to distract the audience. When you watch the video, you'll see I used flying birds, dust waves and an explosion from ProductionCrate. I also used my own Quick Cheats template to improve the final look of the scene.