My question was how to build the datas ? Is it a list of X, Y, VALUE for each column if the live.grid object is in matrix mode ? I've tried this, it failed and when I've opened again the inspector window, the datas were then completely different ? :-(
Ok, I still have no idea of the numbers, but I have managed to set initial values with the use of pattrstorage. So I save as a preset the pattern I create in live.grid, and then have a look with clientwindow. I then get the values I find there, and paste them inside the inspector window of live.grid (with Initial Enabled).