How can i rejoin the edges like “Autocad” ?
Because after clean the edges disappeared…
Use Line, Circle, Offset tool, or 1001bit (for chamfer, extend) extension.
Learn the basics of SketchUp at: https://learn.sketchup.com/
If you are running Cleanup on this, don’t! It LOOKS like you are running the command to merge all faces, which is removing enough edges so that all faces touch. If you have a 2D floor plan this will toss a bunch of wall edges (which I suspect is what we are seeing here). Reserve that command for AFTER the walls have been pulled into 3D.
EDIT: As for cleaning up the loose edges, just use the line tool to reconnect the edges.
Ok, thank’s for the advice !!