what is the eval DAT?

 The Eval DAT creates a table that adheres to some rules that you give it.

The first input is typically a "dumb" table that has no expressions, it might just be a row of table labels like "position, x y z".

The second input is a table with expressions. These are evaluated along the columns.

You can enter information into each table using a text editor. The columns are separated by TABS.

eg you would type: index TAB x TAB y TAB z to create 4 columns

To make the eval dat use data from the dumb table you would type "me.inputCell" into the appropriate "cells" of the 2nd input table.

You will most likely use expressions like

(me.inputRow)/op('noise1').width

op('noise1').sample(x=me.inputRow,y=0)[0]

to create data.

The first is taking the row number of the table and dividing it by the width parameter of an external noise node to get a fraction.

The second is setting the cell value by sampling the rgb value of "noise1" at x,y and taking the first value (which would be red)

You can also set the overall size of the output table via the first or second input tables. This can be changed in the Eval DAT's parameters.