Henry

There are subtleties associated with the choice between using walls and lines with -outline set, that go beyond appearance and internal passage shading.

This from https://therion.speleo.sk/wiki/drawingchecklist

Walls (and lines with -outline in/out) define the outline of the scrap.

Walls are just a special type of line that;

• has the option '-outline out' set by default,
• clips many symbols that typically only appear inside the cave passage (unless '-outline none' is set),
• have their own special subtypes, and altitude labelling, that are not available to other lines,
• are used by the scrap join algorithm to decide which line ends to join (for visible wall lines only),
• define the shape of previewed (above and below) scrap outlines (other linetypes with -outline set to in or out do not do this <unfortunately>).

Like Martin, my preference for surface bluffs and similar features, after experimenting some years ago, is to use…

line wall:pit -outline none -clip off

(I think the second bullet point statement above, in parentheses is incorrect, maybe should read – unless ‘-clip off’ is set)

If I wanted a different appearance to line wall:pit, I would probably redefine the symbol for wall:pit rather than use a non-wall linetype, so that I can retain the scrap joining and preview characteristics of walls.

Bruce

From: Therion [mailto:therion-bounces@speleo.sk] On Behalf Of Martin Sluka via Therion
Sent: Tuesday, 14 February 2017 11:55 PM
To: List for Therion users <therion@speleo.sk>
Cc: Martin Sluka <martinsluka@mac.com>
Subject: Re: [Therion] Surface or Canyon walls

It is from AUT symbol set:

Better idea is "-outline none -clip off" option, because it is surface morphology, not a part of an underground cavity.

m.s.