Hello, I'm new in Houdini and trying to follow the official tutorial in following link.

HOUDINI FOUNDATIONS CREATE A TASK WORKFLOW TO BUILD CITIES [media.sidefx.com]

At the page 16, 4 result based on different city grids supposed to be created by wedge node and I got 3 right but 1 failed.

It seems like one task in ROP Geometry Output (create_building) is failed in some reason.

Is there anyway to avoid this error ,or is there any procedure to solve this kind of situation?

Any advice are appreciated. Thank you in advance.