Naming something is the first step toward figuring out what makes that thing different from all the other things in the world. In a SketchUp 3D model, this idea isn't just a philosophical concept. When you use the Classifier to embed data into groups or or components, those groups or components become objects that can be managed. 

What Happened to Layers? SketchUp’s Tags are an updated form of what was called Layers in older versions. Tags provide the same functionality that Layers provided and more.Tags help you organize the objects in your SketchUp model and control their visibility. SketchUp allows you to hide tagged objects in one click rather than select each object individually. Hiding large chunks of your model using tags helps to find things faster and even speed up SketchUp a bit too.

With the Outliner in SketchUp you can view a model's groups, components, and section planes in a hierarchical tree. The Outliner panel makes it easy to:

As you create 3D models in SketchUp, you create an entity whenever you draw a line or face. Combining lines and faces into a group or component creates a special group or component entity. Each entity in a model has attributes, such as its measurement, the layer it's on, and more. If an entity is a component, then it has an instance and might be a solid (or not) or have other attributes, such as an IFC type. Depending on what you're doing in SketchUp, you might need to know or change an entity's attributes. To do so, look in the Entity Info panel:

SketchUp components enable you to reuse objects. For example, pretty much every building has at least one door and window. Instead of modeling these common objects, you can insert a component that someone else has already made.Like all geometry in SketchUp, a component is still made of edges and faces. The edges and faces are simply part of a special component group. (You can also create components to reuse your own geometry, but that's covered in Developing Components and Dynamic Components.)

In SketchUp, you can add four types of text:

With SketchUp’s Solid tools, you can create new shapes by combining or cutting one shape with another, making it easy to model an outer shell or joinery.

Using the Soften Edges feature, along with the Smooth edge property, changes the visibility of edges and can make your model look more realistic with less geometry. As an added bonus, it may also improve your computer’s performance.Understanding the edge propertiesIn SketchUp, the following properties, in various combinations, enable you to control edges’ appearance:Soft: When you soften an edge, the edge is hidden, and the faces that the edge bounds become a surface entity.

Your model is more than just straight lines. SketchUp can help you create curved geometry using arcs. Before you begin drawing arcs, here are a few handy details about the way arc entities work: