The accuracy command changes the tolerance in the Newton method for projection. For example, use
accuracy 10
which means there is an increase of the maximum number of iterations by a factor of 10 and the tolerance is decreased by a factor of 10.
However, if you are only projecting to a plane (i.e. no other surface is also being projected to - no iterative Newton method is invoked) then the projection to the plane is a one step projection and increasing the accuracy will not help.
The precision of the computer can be the issue in this case. A 32 bit version of TrueGrid® (which is usually run a 32 bit system) only has 7 digits of accuracy. Projections usually require a square root and a divide, which introduces numerical error in several digits. It is more complicated than that, but this is sufficient to understand the issues. If you have a point , for example, that is 1000 units from the origin, then you already consume the first 3 digits before any projection is made. Of these 7 digits, there are only 2 left for precision calculations.
If you have a 64 bit system and you are running tgd, then you have more precision and the accuracy command gives you more accuracy.
