# What is the output of the Attribute Compare node?

Hi everybody,

I am just trying to more seriously learn geometry nodes and understanding the math (I am not good at math). I have been following a tutorial to create procedural buildings and although I managed to complete it I am not completely sure I understood all the math.

The part I need help with is when the artist uses an Atribute Compare node to create a new attribute that will define a mask to place the ceiling tile of the building, only the last tile on the top.

There are two things I am unsure of, I do not know what the value of pZ is. Is it the Z position of each of the vertices in the grid? Is there a way I could visually see these values ?

The other thing I do not understand is the result of the Attribute Compare node. It is set to greater than so my understanding is that if A is bigger than B the output would be 1 and it would be stored in the attribute “roof”. But if I tweak the values of the math nodes that connect to B I can have more roof tiles. I thought the output of the compare node could only be 1 or 0.

The “roof attribute” is then used as a mask in the Point Separate node where the Geometry 2 socket is connected to a Point instance node. The same Idea is used to change the tiles on the bottom row and pillars on the sides.

It feels pointless to follow tutorials if I do not fully understand what is going on. I would also like to polish this system further adding more variation but I need to be able to understand how to “select” vertices in the grid to assign different tiles. Can someone help me understand what I am missing?

PS: The tutorial I followed is by Chong 3D:

Can’t be of much help but I have seen that in 3.0 there is a viewer node.

https://docs.blender.org/manual/en/3.0/modeling/geometry_nodes/output/viewer.html