Hello Georgios, Thanks for your reply, but that was not quite it. In the original code I used fieldPlot:=DEplot(...): display(fieldPlot); - I must have missed the ':' when simplifying the code. But I'm certain the problem is not there: If I use scene=[t,N(t)] the empty plot (only the axes) will turn up, but scene=[P(t),N(t)] will turn up a slope field with a the curve corresponding to initConds. Is the problem reproducible for others running Maple 10? Regards, Mads

Hello Georgios, Thanks for your reply, but that was not quite it. In the original code I used fieldPlot:=DEplot(...): display(fieldPlot); - I must have missed the ':' when simplifying the code. But I'm certain the problem is not there: If I use scene=[t,N(t)] the empty plot (only the axes) will turn up, but scene=[P(t),N(t)] will turn up a slope field with a the curve corresponding to initConds. Is the problem reproducible for others running Maple 10? Regards, Mads