How do you fill in the objects so that they appear as a solid?

I have only just started using SketchUp and I am finding it annoying that my objects do not always auto-fill to become a solid, and then when I click on an area to make a solid, SketchUp simply says “Not a solid”.

I am trying to sketch up the frame work for a pergola, and I have been battling for a week now.

I am finally doing the 50mm x 50mm rafters, but again, the surface area I wish to have filled so that it becomes a solid does not happen as per my diagram (hopefully it uploads) - HELP:

SU is a surface modeller, only edges and faces, a solid is always empty but it is a complete skin with no holes or extra faces inside. It also need to be made into a group or component to be seen as a solid. The grouping also stops the geometry sticking together.
So to draw your rafters I would draw a 50 x 50 square, double click right click and make it a component, then double click to open it for editing and use pushpull to give it length, then click away from it to close in. You should then have a 50x50x? white rafter that is a component. White is the front face blue is the back and shouldn’t be seen when constructed correctly.
You can now use the move tool to copy array the component so you have multiples the same.

It will look a little different in the web version but the process is the same.

Well that certainly looks 100x easier than what and how I’ve been doing it!
Thank you - I’ll give that a try and reply should I still have any further issues.
Kind regards.

Yep - its a usual approach to make components for identical objects and insert copy of them in the model - saves space in the file and changes will be appearing on all instances of the component :crazy_face: