and btw asking the difference between retouching a human and a building is just funny
Not funny at all.
Just like products and people, built environments are marketed as well by designers, builders, developers and realtors. And they need good, clean images of their product - The Built Environments.
They all want to show/describe/market their works just as clearly and palatable as product designers and clothing designers.
Architectural photographic works are produced for various purposes. Depending on the purpose of the images, the retouching needs will vary. Exmaple: A documentary of a historic building versus to marketing a new mall.
When it comes to retouching architectural works, here are a few things to consider, for starters:
1. White balance. Colors need to be rendered as close to the colors as intended by the designer
2. Perspective correction is crucial - even when tilt shift lenses are used
3. Cleaning up distracting elements such as power lines and telephone lines etc.
4. Composites are not uncommon, which invloves certain retouching skills
5. If it is an old building, you might have to retouch stains on the walls, for example.
6. HDR and the related retouching work is useful more in architectural photography than in people photography
7. Panaromic stitching is needed often times. There is retouch work involved in /resulting from panaromic shots.
8. Unless paid models are used, oten times people need to be removed from images of built environments
9. In some cases, the building is designed but yet to be built. There is plenty of retouching to do when super-imposing the CGI shots of the building's computer model on to the image of a site/location
There is no such thing as a standard procedure. Procedures and methods may develop after working with a certain client for a while, depending on their specific needs and requirements.