2D Output Scale Dependant Error -- metapost exit code -- 3

Hi

Wonder if anyone knows what might be going on here?

The attached log file was more than 6MB and 135,000 lines and I have trimmed out most of the offending error reporting (which were I think was pretty much identical)

Have only recently noticed this problem, so may be related to changes in the last few Therion updates.  Many of my datasets have not changed for some months.

My pdf map will create OK at scales of 1:500, 1:1000, 1:2000, 1:4000, but not  1:4500 (gives a single error as attached) nor 1:5000 to 1:6000 (gives many thousands of errors, 6MB and 13MB respectively).

Interestingly 1:7500, 1:9000, 1:10,000 and 1:20,000 compile OK.

The pattern seems to hold for low level cave maps as well as for maps of collections of caves.

This is particularly a problem for distributed systems where I get squeezed between the 5.5m pdf size limit and the above scale limit, but don’t want to go to the much larger scale.  (I could try using atlas base scale, but I’ve had enough experimentation for now).

Regards

Bruce