Arcpy problem: ERROR 000728: Field 10 does not exist within table Failed to execute (PolygonToRaster).

[David_Brooks]

I've got the following script to loop through a  polygon dataset, but I keep getting a strange error that I can't fathom. 

ERROR 000728: Field 10 does not exist within table
Failed to execute (PolygonToRaster).

I don't have a "Field 10" so im not sure why the PolyToRas tool is trying to access it.

Here's the script

# for loop to loop through each "group_extent" polygon in turn and create shadow polygons
with arcpy.da.SearchCursor(group_extent,['SHAPE@', 'GroupRef', 'Species', 'MaxHeight']) as cursor:
   groupCount = 0
   for fc in cursor:
      # variables
      shadowRas = "shadowRas"
      shadowPnts = "memory\shadowPnts"
      shadowPntsJoined = "memory\shadowPntsJoined"
      cellsize = fc[3]      
      # polygon to raster
      arcpy.conversion.PolygonToRaster(fc[0], cellsize, shadowRas, "CELL_CENTER", "NONE", cellsize, "DO_NOT_BUILD")
      # raster to point
      arcpy.conversion.RasterToPoint(shadowRas, shadowPnts, "Value")
      arcpy.management.DeleteFeatures(shadowRas)
      # join group data back to shadowPnts
      arcpy.analysis.SpatialJoin(shadowPnts, group_extent, shadowPntsJoined)

Any ideas what's going on?

[David_Brooks]

@JohannesLindner @Luke_Pinner thank you both. Excellent suggestions. Have implemented Johannes solution with success 👍