06 Check the result
To see the effect on your image without the cropped areas, click on the arrow tool on the top toolbar. This is how your image will now appear if you export it as a new file. Don’t forget that Capture One Pro is fully non-destructive. Everything that’s been done so far can be undone or re-done as required.
07 The final image
I think this is a pretty good result – it’s certainly more ‘correct’ from an architectural point of view. In an ideal world, you’d shoot this with the camera level to prevent any perspective distortion in the first place, though this would leave you with the problem of filling the foreground, and the building itself would only be in the top half of the frame.
The alternative would be to use a special ’tilt-shift’ lens, raising the front of the lens so that the building would fit in the frame without having to tilt the camera.
Often, though, these approaches are impossible and impractical, so it’s nice to know you can also fix the problem in software!