Hi Anthony, thanks for posting the circle trimming file.

The problem there is again related to the small numeric scale of the objects - your circle there has a radius of 0.0018 and that is too close to the default tolerance level of 0.001 units.

You can solve this by going to Options > General and switching your units to millimeters instead of meters. After you do that your circle will have a radius of 1.8 units instead of such a small numeric value, and then the trim will work fine after that, see the attached example file.

Like I mentioned before, you'll likely run into a variety of problems trying to work with objects that have such a small numeric size - try working with your objects at a larger scale (but don't go overboard into the millions of units though! - think more along the lines of 10 units or so) and things should generally work better.

I'll see about tuning up the Trim command for v3 to use the relative tolerance mechanism which should then make your original example work. The relative tolerance system uses a tolerance that is calculated as a fraction of the object's bounding size so it adapts itself to smaller objects and that works better in situations like this.

- Michael