Assuming you want to keep the section cut -- Use the Section icon "display section plane" to toggle display of the transparent plane. There is also an icon that toggles display of the section cut.

hmmm, if you go to view->face style, which option have you got checked? Normally it should be 'shaded with textures'

...or start your line and when you see the red inference, press the Shift key to lock the line on axis. Now you will be able to use any other inference (say the endpoint of a parallel line) but keep staying on the red axis. This also works with other tools (such as the Move tool for instance).

I used a method similar to Remus but with ctrl+erase between steps so that clean up is quicker and easier. Have a look at the attached file. [image: 9kSK_Twistedcollumn.jpg] Twisted collumn.skp

G'day Sweet glad that helped, sorry about that, as i said at 5am not the sharpest knife in the block you can use trapezoid shapes , just make sure that your line tool is inferenced in the direction you are taking the line blue = up/down red left/right etc. colour by axis helps a lot, lots of little tricks like that on the boards. [image: qWGa_stairlanding.jpg]

hi sweetluge, did you have switched off the floor layer? if yes, I thinkt your line already exists, it is just made invisible. now you are trying to draw another line in the same place (SketchUp doesnt understand that, because it knows there already is a line). like the others said: the only way is to build groups/components - which you should use in any case in order to keep a model organised and structured