Some quick templates to replicate the triangle door I've used for base building. There is some visual clipping from the tek walls, but I've found some skins do cover it well. For example the Amissa structures mod covers it well, and the Crystal Structures mod can be used on the tek door to make it less noticeable as well. If you don't want to use mods building it out of tek gives minimal clipping, or you can just exclude the tek door and leave it open.
A very large Gazebo like base I used for raising Rhynio's and other babies remotely before cryopods or other options were available on my server. Features multiple levels that can be easily closed off if you'd like a more secure base, but I personally used a forcefield.
This was first big ASA project from launch, a Viking inspired lodge using all vanilla structures. The interior is a blank slate so you can customize it to your liking. I took a lot of inspiration from a youtube base tour, but sadly can not find the video or channel any longer. If you recognize it please let me know and I'll link it and give credit.