Higher Quality Shadow Maps
Rookie mistake - raytracing to get crisp shadows increases render times to unreasonable heights. Instead, here is the general method I employ to get good looking shadow maps.
Try increasing the ‘Shadow Map Size’ parameter so you get more detailed shadows. To see a good result, try changing the default 256 to at least 1500. The scale goes up to 10k, but you may develop crashing problems around 8000.
The other unnatural looking thing about shadow maps is the distance at which the shadow falls from the object. This can be adjusted with the ’bias’. Changing the default setting from 4 to 0.1 looks pretty close to a raytraced setting.
Finally you may notice these shadows are now too crisp. For each pixel in a shadow map the ’Smp Range’ value controls how many adjacent pixels are sampled and their value. This allows pixels along the edge of shadows become gray. As a general rule, if you double the ’Shadow Map Size’ you will also need to double the Smp Range to create edge softness.
Of course for every scene there is a threshold where the higher setting on the shadow mapped light will actually take longer to render than the raytraced light. That however, you will have to discover for yourself. Good luck!
