Hi Guys
The image below shows a flat plane floating in a room at a random angle. Is there a plugin that could project where that plane would strike the vertical walls if it were extended?
Basically I am looking for an easy way to obtain the dotted lines shown in the second image.
Thanks as always,
You can use the “On face” inference with inference locking. Or the “On edge” inference to get the points where the face edges intersect the surrounding walls.
Thanks Anssi.
So in this example I can effectively slide the plane along the green axis to intersect with the side wall, and project the edges onto the back wall to get my lines.
The thing is, this is a pretty simple example and some of these rooms are very much out of square so I was hoping for a single click plugin 
Thank you @mihai.s
I am downloading Projection Tools now, and will report back 
Edit:
Thanks for the recommendation @mihai.s - it works well but creates many unwanted groups. Probably not fully compatible with 2025 on PC (EW says 2016).
Easy managing groups created by the Projection Tools extension
You can place a section plane on the face. Then choose that section plane, right click then select “Create Group from slice”. This way may not the best, but simple.
That is GENIUS!!!
That’s so simple but exactly what I was looking for. That method will form part of my workflow for every project going forward.
Thanks again.
I would just use guides. Select the tape measure tool and click on the edge of the plane. The guide line will disappear going through the wall. Then place a guide from the wall edge the the intersection of the guide at the wall surface.
Thanks Ivan. It’s often more complicated than that. The profile in question is always the underside of a multi ton glass roof, and the surface is usually a mesh of an un-square, uneven, old cottage. In the example below it took literally hours to plot where the supporting metalwork had to go. Taking a section on the glass underside and using ‘create group from slice’ would have allowed me to just measured it off.
Hence my genius comment for @Cyentruk
Mesh
Gotcha, All the above suggestions are good. I was just tossing out what seemed simple to me. The beauty of Sketchup is there are many ways to get things done. Another thought is to set an Axis normal to the plane then any geometry would follow the plane (Axis). Switching active Axis can get you in trouble or get confusing. There are a couple of Axis manager Plugins that simplify managing them and makes it way to reset to the “World” Axis. That might help If you need to model normal to this plane.
This is so true
