[Therion] Showing a lower scrap down a pit in an overlying scrap

[Bruce]

>To make pit transparent just add to line pit option '-outline in -clip
off'. 

This works well if you only ever present this scrap in maps with no internal
colour or both coloured upper and lower levels in their true positions.  If
like I have been doing, the scraps are sometimes presented one above the
other, and others they are presented offset (two different outputs for two
different purposes), then the upper offset passage has a 'hole' where the
pit should be.

It is perhaps not so much a therion problem, more the user has to decide
whether to compromise on colours, variety of presentations, or edit all of
the pits each time the presentation is changed.

And the last bit of that sentence gave me an idea.
The revise statement would allow the user to quite easily change the outline
parameter for any 'non-standard' outputs without having to manually edit it
each time.  

If the pit is defined in scrap1 as Martin suggested at the top of this post,
and it has -id scrap1pit1,
then perhaps in the map definition with the lower scraps offset, the revise
statement could be included...

map LowerScrapOffset -proj plan
   revise scrap1pit1 -outline out           # restore shading to top scrap
   scrap1 at s1
   MapofScrap2 preview 100 000 metres below # MapofScrap2 contains scrap2 at s2
endmap

Simple? I'll find some of my irksome pits sometime and test it.


Bruce