[VB] Incomprehensible Index out of boundaries

Hello,

I am currently working on a VB.NET Script to generate a height map at a custom dpi directly from a brep.

The code is working fine until 13dpi (for my computer) and then, starting at 14 an error occurs :

error: Index was outside the bounds of the array. (line: 0)

I fail to see how this is possible and where the pb is since it cannot locate it more precisely.

Please find my file attached (you will need to indicate a path to save the image file)

Thank you.

Tristan