Illustrator CS6 beta GRID question.

Question

Can someone who is beta-testing Illustrator CS6.. Does it yet allow you to change the grid to Thousandths?
I use Illustrator with CADtools plugin for architectural drafting.  I need to adopt a drawing to 1/8 (.125) or 3/8 (.375) scale.  As it is, CS5 can only change it to .12-.13, or .37-.38 respectively.  This throws off the scale of the floor plan.
Thanks.
PS, I did put in a request when both CS4 and CS5 were out, so hopefully this was looked into.  With the increased power and features of Illustrator, allowing draftsman to use it as a CAD program would be very beneficial.

Answer 1

People might actually start complaining if they get to see the 14+ accurate decimals *everywhere*' as that is what Illustrator does its internal calculations with.
Actually, Illustrator's internal calculations are far worse than that, and it's a reason Illustrator doesn't show a lot of digits.
The main problem is that all coordinates in Illustrator are represented internally in the rather awkward units of 1/2048 of a point. While convenient from a binary standpoint (11 bits for the fraction), this value -- suppose we call it a 'zip' -- means that many values, both in points and in other units like mm, cannot be represented precisely.
Since there are 2048 zips in a point, and 72 points in an inch, there are 2048*72 = 147456 zips/inch. Values like 0.25in (36864 zips), 0.125in (18432 zips),and 0.0625in (9216 zips) can all be exactly represented. But something like 0.1in cannot, since it would be 14745.6 zips and the number of zips must be integral. The closest we can come is 14746 zips, or 0.10000271267in.
Millimeters are even worse, since even 1mm cannot be exactly represented in zips (1mm would be 5805.35433071 zips; we must be content with 5805 zips, or 0.999938965mm). 0.125mm (725.66929 zips) gets changed to 0.125056966mm (726 zips).
Generally the values in Illustrator are shown in the user interface rounded to three digits, so you don't notice the slight inaccuracies. They're still there, though. For example, draw a 0.125mm square and scale it to 10000% -- the resulting square will be 12.506mm, not 12.5mm.
DF