What is the internal precision used by Adobe Illustrator? Or put another way, what internal representation does Illustrator use to store coordinate data?
Try this (I'm using CS6):
- Zoom in as close as Illustrator allows (6400% in CS6).
- Draw a circle.
- Resize the circle to 0.001 × 0.001 pt.
- Resize the circle to 10 × 10 pt.
Here's what I get when I do that:
This is obviously an extreme example, but I have experienced similar distortions in more realistic scenarios when objects have gone through extensive editing. To avoid this, I have had to resort in some cases to working at an enlarged scale and only resizing my artwork to final size at the very end.
Clearly, Illustrator's internal precision is not infinite. It appears that coordinates are ultimately rounded to an integer at some small scale (I assume some fraction of a point), such that rounding errors can accumulate, eventually culminating in visible distortion.
Can anyone shed some light on this?