Hello Remy!
Thank you for your answer. I've been away from the computer so I couldn't answer before. I print the model that way because my teacher in the 3d printing course told me that it will be faster that way. The problem I have found is that at the moment of looking at the gcode file in different computers the layers appear and dissappear depending on which computer I see them. It is very strange and I don't know what could be happening.
Anyway, I really appreciate your answer and thank you a lot for that.
My best Regards
Adolfo