Comprehensive building studies with good quality drawings are difficult to find online. It becomes even more difficult if you have chosen a building to use before having checked sources or done any searches.
Test your choice - how much information can you find? If you're struggling to find sources, consider why you chose that building. Are there other buildings you could look at which feature the same properties?
Try these image collections:
- ArtStor - Drawing and photos. Good for major 20th century architecture and architects.
- RIBApix. - British Architecture and architects. Drawings and photos.
- ArchDaily - Might include sketches, technical details, plans, elevations, photographs, or visualisations.
- Dezeen - Could have drawings, technical specifications, blueprints, elevations, photos, or visual representations.
- Architects Websites - Varied: may be limited; may or may not be downloadable.