Yes! That's what I was looking for! Thanks a lot!

I mean, the CABIN has a door to the TUNNEL

They are two objects, but must be connected exactly. Thanks again!

Hi! Thanks for your reply! Sorry, I have to explain better! What I'm looking at is a full hole in the CABIN object, as if the TUNNEL object where a solid extrude

Hello Dr.Sassi!

Please take a look at the scene enclosed. I'd like to know how can I make a hole in the CABIN that connects the TUNNEL
Thanks!
JavierBooleanHOLE.c4d

Hello! The normals were wrong! Now is fine! Thanks a lot!

I'm one year into this project and sometimes need a break or I'll turn crazy!

Hello! Sorry for the reply so late! I've been out the game stuff for a break. Thanks a lot!

Hello Dr.Sassi!

I'm building things for a game project. I found an error with a Boolean that I don't understand, as I have other segments of the same type, with no errors. Please take a look at this scene; I can't use booleans if I use slice to the object 02. However it worked in other objects like that, see 01
Thanks for your helpBooleanError.c4d

Hi Dr.Sassi! Thanks for your solution. Let me ask you; my original scene worked fine adapting to all curved walls. Will be possible to reduce the number of steps (clones) to half up to the cube added, without changing the angle, shape, etc ? Seems this option harder! Thanks again
WallCircularStairs02.c4d