<p>If you get bad rendering on a big curved flat surfaces try this...<br><br>Open the surface. Here I deleted one point in the middle and all connected faces were radially deleted. <br><br>Use the Cap Open boundaries tool (ctrl+o) and play with the jog in the "slope" settings.<br><br>Voila a new mesh "spiderweb" closed this flat surface and rendering looks great on this.<br><br>NOTE. do this when you are ready / done with modeling. The more mesh you have the harder you can work with it. </p>