The biggest tip i have found to get this work is there can not be anything above it. Looking at a porch try to place one with a ceiling above it. Wouldn't place, it wanted to place it on the ceiling above. Deleting anything above where i want to place it has solved all my issues with placing it. Not ideal, but works.

引用自 Alley_Killa：

The biggest tip i have found to get this work is there can not be anything above it. Looking at a porch try to place one with a ceiling above it. Wouldn't place, it wanted to place it on the ceiling above. Deleting anything above where i want to place it has solved all my issues with placing it. Not ideal, but works.

From what I can tell, that is behavior inherited from vanilla fence foundations. I noticed the same thing happen when trying to lay down a dino pen where part of it went under an overhang from my house. You can build above it afterwards with no issue, but the fence has to be laid down first.