Here are some examples where taking good photographs is difficult. Perhaps you can see or extrapolate your particular problem.
• The building facade you are modeling has cars parked in front of it and you cannot see where the building meets the sidewalk.
• The building you are modeling is surrounded by earth berms or uneven terrain and you cannot see the bottom edge of the building.
• The process plant you are measuring has a large walk-way in between where you want to take photographs and all the boilers, pipes and valves you wish to measure,
• The heritage school house you are modeling for your renovation project is surrounded by large old trees.
• The tall tower you are measuring has a platform on top with some compressor housings that you need to measure but you want to take your photographs from ground level.
• The automotive part you are modeling has many smooth curves and it is difficult to uniquely identify a single point on that surface in more than one photograph.
• The object you are modeling has many curves and edges but not many good distinct points which you need to mark and reference so you can orient the photographs so that the Curve and Edge Tools can be used.
• The building you are modeling is quite large and you want to get both an overall model but with lots of detail. When you take the overall photographs, the details are too fuzzy to mark but if you take lots of close-up shots it is hard to get an accurate consistent model.
• The building you are modeling is quite large and due to the long focal length of your lens you cannot get photographs that encompass the whole structure.
On the other hand, there are many objects, both large and small, that you can take clear photographs of and in which you can identify each point precisely and uniquely. There are also many work-arounds for the problems listed above.