Campaign Rule. A creature that takes damage from an illusion can make a Wisdom save vs magic to disbelieve the effect. If recreating an effect, the caster must know how to use the effect (as a spell, ability, item, etc.). Any effect created by the caster operates at their caster level. The caster must have encountered any creatures they create. Creatures created by the spell are average specimens with regard to statistics/attacks. Total hit dice is limited by caster Intelligence score. The caster can break up the area of effect within the range of the spell so as to allow missile weapons being used by illusory troops. Only one effect can be created per spell, ie. one fireball, one group of goblins, one wall, one pit, one ship, etc. Trappings are possible, for the previous examples: burning/smoking furniture or clothing, various kinds of equipment or bags of gems being carried by the goblins, a wall adorned with pictures or a hole or writing, a pit with spikes or covered in green goo, a ship manned with pirates (that don't attack but move around believably), etc.If there is no audial component and the illusion requires one - illusory creatures in melee, a raging fire, etc. creatures nearby get an immediate save for disbelief. If reasonable noise exists, the GM may disregard the immediate save, for example a group of bowmen firing in battle.This extends to other effects, fire without a thermal component, etc."Interacting" with an illusion does not grant a disbelief save if the caster is actively concentrating on the spell. Otherwise, interaction must be tactile - ie. through feel - touching by hand, etc. It is not possible to simply look at an illusion and attempt disbelief.Once disbelieved, the illusion is seen only as the barest outline, ie. it does not impede vision or color at all.