Trouble subtracting from a solid

I’m new to SketchUp and so far I like it. I will need to later solids as regular task. I have been practicing and I run into a problem when I try to subtract solids. I am able to create “components” just fine. But when I attempt to subtract two “components” one is unable to be selected. The message I see on the screen states, “not a solid”? What am I doing wrong?

Evidently one of your components doesn’t meet the definition for being solid. In simple terms the edges in a component or group must be shared by exactly two faces. No stray edges, no holes in surfaces, and no internal faces.

Without seeing your SketchUp model it’s just a guess as to what you are doing wrong.

You also want to make sure that faces are oriented correctly. No exposed blue back faces.

Try Solid Inspector.

I am attempting to use this program to create fab drawings for kitchen cabinets. I’ve been successful drawing plywood boxes with grooves routed in them for assembly. My current challenge is making the doors. The solids do have mortises drawn in them already. (Basically a rectangular shaped block 3/4" thick with a 1/4" x 2" x1" deep pocket removed.) I successfully subtracted from the original solid in order to make the mortises.
Now I am trying to remove a groove 1/4"x1/4" running almost the length of the piece. Unlike when I subtracted the mortises, I am now running into an error message saying it’s not a solid. Are you saying that that is because I already have a “hole”, (mortise), in that surface? I would think I can “cut” more than one hole in a surface, right?
I appreciate any help you can give me.

I wasn’t referring to a mortise as a hole in the surface. I was referring to missing faces. You should be able to subtract the groove after the mortises if you want. Why your door stiles aren’t considered solid after subtracting the mortise is anyone’s guess. As I wrote yesterday, without seeing your model it is just that; a guess.

I deleted everything and started over. (Keep in mind I’m trying to understand how SketchUp “thinks”). I started with a new stile and placed the rectangle on a surface where I intended to mortise. Then I placed another rectangle on the same surface adjacent to one another. I have the ability to create two separate mortises essentially attached to one another. Why is the depth constrained by the depth of the first? I then created a mortise on the same face but not adjacent to the other. I was able to move the surface of the mortise and create the piece the way that I wanted. But can you help me understand why in the first scenario I was constrained?

For the third time, not without seeing your model. I have to believe there’s something wrong with your objects that is causing this since it isn’t a normal thing to have Subtract make the object non-solid.

Here a simple door. I’d use Trim from Eneroth Solid Tools or BoolTools2 instead of the native Solid Tools because those extension respect the component-ness. And instead of making blocks to cut the mortises, why not let the tenons do that?

FWIW, in these pieces all of the mortises, grooves, draw bore holes and at least half of every dovetail joint were done using Trim from Eneroth Solid Tools. They both have kumiko panels with half-laps that were done the same way but I hid those to reduce the clutter.