Issue with Components Not being Solid

I’m trying to build a Sketchup model of the Roubo workbench from a woodworking book I own. I have built the legs as 4 separate components with the hole for the stretchers (lower braces) trimmed from them using the “trim” tool. At this point in the model, I’m trying to trim the hole for the legs to go into the top, but when I select any of them I am given the “object not a solid” issue. While I can work around this by making a new group with the correct dimension to subtract my tenon (tongue) from the top to create the mortise (hole), I’m trying to understand what I’m missing in creating components that work as solids, or how to fix my “non-solid” components.

Thank you in advance for any help you guys can offer!

Workbench.skp (124.6 KB)

The top as a whole group has many “internal walls” made by stacking all the pieces together. You would need to delete those and it will perform like a solid. The “solid inspector” plugin can be useful for inspecting geometry as solid and can often fix problems or point them out.
I’d make the top one simple solid and add the line detail afterwards, or you would need to perform the solid operations on each individual plank (with the leg top tenons) that comprise the top.

Thank you for the reply! Part of why I was trying to make this work is that by using the individual components I can approximate my lumber shopping list, though I can see making a separate model to achieve that.
I’m coming across the same issue with a different component in the model, so I will try your suggested plugin. Again, appreciate the response.

A couple of simple issues will get things working for you.

To start with, your legs should be 4 instances of 1 Component, rather than 4 Groups.
Edit: I just noticed the name of the leg groups, Difference, this tells me they are groups rather than components as a result of using solid tools.
Currently those groups are not solid because the ‘holes’ are touching, which means you have one edge that adjoins 4 faces, while solids must contain edges that join only 2 faces, no more or less. If you make the holes either deeper or shallower, it will fix that issue and the legs will become solid.
The stretchers are components with two groups nested inside, therefore not solids. If you explode those groups and remove the internal face the component will become a solid. The front and back stretchers can be instances of the same component, flipped.

Awesome, thank you for the assist there. I’m guessing the outer shell tool is the one to use here? I haven’t yet had an instance where intersect has helped me…
For what it’s worth, I had 4 instances of the legs separate as they technically all have different cuts, or at least 3 of them will be different based on what I have to do with vises and whatnot.

Really appreciate the help!