I remember in my first year out of college I was working with our racking vendor to put together a future state plan for a fully built out interior. Step one was to go column to column and measure the actual distance between each because a 1 to 3 inch variance could throw the whole thing off. This surprised me at the time because the spec was for all columns to be exactly 50′ by 50′ apart. But nothing ever happens that perfectly or cleanly.
The real world is not full of straight lines, it’s full of lines that look straight but are actually slightly curved. It’s full of lines that actually have angles in them part way through. The straightest path is actually a large arc. Lines that appear to be going straight today shift over time as pieces of this world expand and contract due to temperature changes. Planning on straight lines will never win.
Sometimes a line that appears straight at 50,000 feet looks like a wave pattern at 2 inches. Sometimes a straight line at 2 inches is a clear curve at 50,000 feet. Perspective will always play tricks on us and usually not in the direction that we expected it to happen in. Don’t just measure twice, cut once. Measure with multiple devices from multiple angles and double check that you are measuring the right thing to begin with. That straight line may not be what you think it is to begin with.