[Therion] Entering survey sketch without walls

[Bruce Mutton]

> If I draw only that part of the column which is in each scrap, can I still use "-outline in"?  
No, those remain -outline out.  
Also your sketches for surveys should not include the parts of the pillar walls that have not been surveyed!

> Will I need to use line joins to get the two parts of the column to come together?  
No, use join scrap1 scrap2 -count 2
And you will need to replace line wall -subtype invisible with line wall -visibility off as is intimated in https://therion.speleo.sk/wiki/drawingchecklist#wall 

>And will that result in a column that is entirely white on the inside?
Yes, but only once you have all wall lines in place and parameters for all lines correct (-reverse, -outline, -subtype, -visibility)

Bruce