ShadowSlopeBias

Controls how accurate self shadowing of whole scene shadows from this light are. This works in addition to shadow bias, by increasing the amount of bias depending on the slope of a surface. At 0, shadows will start at the their caster surface, but there will be many self shadowing artifacts. larger values, shadows will start further from their caster, and there won't be self shadowing artifacts but object might appear to fly. around 0.5 seems to be a good tradeoff. This also affects the soft transition of shadows