Mark Guideline
Plant Engineering > Guideline Tools > Guide. 
> Mark guideline 
This function enables you to highlight guidelines thus enabling you to visualise their orientation and route.
You can either identify the appropriate guideline with the cursor, or activate the Extended part selection with the right mouse button and select the appropriate option.
Alternate edges comprising the guideline are coloured violet and green, whereby the first edge is coloured violet, the second green and the next violet etc.
An arrowhead at the end of the first edge indicates the orientation of the guideline.
Select the Redraw 
function to return to normal representation.
