I think I have mastered extended elevations, and have control of extended centrelines using extend left/right statements within a single top-level file for an entire cave.  This means that it is easy to simultaneously create different extended elevation shapes from the same parts of the centreline.

So just because I could, I decided to reflect an entire cave elevation (300m deep pitch series) after having finished all of the scrap drawings, using;

scrap –flip horizontal and swapping all extend left for extend right etc

Some aspects work nicely, for example;

• Point entity (ie labels etc) alignment relativity is preserved, ie -align bottom-left, when transformed by –flip horizontal, behaves as if it is –align bottom-right, and
• Whole scraps join perfectly, ie  join 01-SpanishParrotElevEXT-s3  02-SpanishElevEXT-s2

However other aspects are not so good, as can be seen on the attached image;

• Arrows are a problem, ie line arrow, when transformed by –flip horizontal, ends up with the arrow-heads on the wrong end,
• -text “<left>…” (ie justified text, whether explicitly specified or implicitly inferred), is not transformed by –flip horizontal, so it ends up looking wrong,
• Joins of specific points on lines end up with undesirable distortion
  join 02-s3-rockb:1        07-s1-wall:0       07-s1-rborder:0                      #top of passage 3 waters apex
                  join 02-s3-rockb:end   07-s1-wall:end   07-s1-rborder:end                 #btm of passage 3 waters floor   

The arrows and text justification are easy, if tedious, to work-around, however I have not as yet figured out how to fix the joins (the ‘correct’ join example in the attached image was modified with Paint.net, not Therion).  I thought it might be something to do with line point numbering swapping around on transformation, but the lines in this example are only 2 and 3 points long, and combined with the shape of distortion, I think not.  Perhaps it is the bezier curve parameters that are twisting it up on transformation?  Not sure how I could fix that.  I also notice that the nearby but unattached rock is distorted as well.

I have not done an exhaustive test on all line types, so there may be others that cause problems. 

Interested in people’s thoughts on whether justified text should be transformed

And actually I am not just reflecting the elevation because I can (almost), I made a mistake at the beginning of the survey, so I really would like to be able to get a clean reflection and produce a quality map.  Any workarounds for the join issue gratefully received.

Thanks

Bruce