[Therion] Centre lines and therion

[Andrew Atkinson]

Hello

We (Wookey and I) are working on the Mulu data set which is using survex 
3d files to import the survey legs. This shows the survey legs within 
the passage where it exists, but not when there is no pasage. However 
what we would really like to do is show the centreline when there is no 
passage, and not show it when there is passage drawn.

Is there any way to do this

thanks

Andrew