In engineering applications, it's perfectly sensible to use float for world modelling, which give you precision of about 1 in 10 million. Then you can use doubl

In engineering applications, it's perfectly sensible to use float for world modelling, which give you precision of about 1 in 10 million. Then you can use double for intermediate results and lose less precision in a long calculation, producing a more accurate result (rounded to float) in the end. Also, if the dynamic range of your data allows it [and for physical application it usually does], you can first rescale it to [0,1] in order to further increase precision. [It's the interval where floats are most dense.] Having worked for a few years now in computational geometry, i'm more and more convinced that "float by default" is the way to go. Doubles should be used for intermediate computations.