# GN; Capturing attributes of Bounding Boxes

When you take the Bounding Box of a collection of instances, each unrealized instance is bounded independently.

For some reason, despite the boxes appearing to be instances themselves, and having no apparent mesh in the spreadsheet, you can capture the indices of the 'non-existent' vertices, for use after realization:

Which can be quite handy. Even handier would be to capture the other exposed attributes of the non-existent mesh...

... but it seems you can't. Does anybody know what's going on, here?

• ...perhaps a "missing feature"? Commented Sep 7, 2022 at 16:24
• @quellenform I guess, maybe something to do with: you know that the box is going to have 8 vertices, but you don't know anything else.. hoping that someone can find it in the code, I suppose.. Ahh.. you can capture the V indices of any instance Commented Sep 7, 2022 at 16:48

Each box has 8 vertices, so you could do a bit of math to get the min and max value per box.

If you want the value on the instances then:

• You are gonna use the'Sample Index' node. set it to vector and point.

• use the 'position' as the value and for the index we will do some math.

• we will take the index and multiply it by 8. this will give use the min.
for the max take this value (Index × 8) and add 7.
make sure to capture on the instances on the instance domain.

If you want it on the boxes themselves then

• You are could use the 'Evaluate at Index' node (or 'Sample Index' node). set it to vector and point.

• use the 'position' as the value and for the index we will do some math.

• we will take the index and Divide it by 8 and floor it (this is in the 'Math' node drop-down menu, of in the 'Float to Integer' node drop-down menu). this will give use the min.
for the max take this value (Index ÷ 8) and add 7.
make sure to capture on the boxes on the point domain.

In add the above cases, you have to realize instances.

[this only works because of the order the vertices are generated in geometry nodes; if you do this on a cube you made by extruding etc. in edit mode this wouldn't necessarily give the the min and max]