Hi, I'm writing a ULP to add thermal vias to certain polygons nets (which I'll specify in a list). I want the ULP to automatically place the vias in a grid, if the grid position has the specified net name on top and bottom layers at that position. The plan for the ULP is to run through all grid positions, check if there is copper on both sides of the board belonging to a specified net name (eg GND etc) then add a via to that position and name the via to make the connection. So the question is, given a specified (X,Y) position on the board, how do I determine if there is a polygon with a certain net name at that position (top and bottom)? In particular after a ratsnest function. Are there any inbuilt functions to do this....any exsting ULPs that are doing something similiar? Any help very welcome. Phil