Remove faces from bottom


I used sketchup for the first time and created a 3d model from autocad dwg file.

the bottom has these faces, how to remove them.


Use the eraser tool.

Wow, that’s ambitious for your first time using SketchUp.

Did you import it as an image, or as lines? If it’s an image, then you may want to start over again and import it as lines.

If it’s actual individual lines, then keep double-clicking until you can select a face, and go to View: Face Styles: Wireframe (select Wireframe), then hit either “Ctrl A” or “Command A” on your keyboard to select everything.
Then go back to View: Face Styles and select "Shaded with Textures."
Now, while holding down shift, with the Select tool drag a selection box around everything.
Hit Delete on your keyboard, or right-click and hit erase.

Let me know if that worked!