How can I show the effects of illusions in Roll20?


My players are approaching a battle with Fraz-Urb’luu, who will have prepared the battlefield in some manner using an effect like Mirage Arcane and several other illusions and deceptions.

Given that I anticipate some characters having the benefit of True Seeing and others will not, is there a way for me to somehow present both the illusory and real battlefield? Ideally the method is practical to implement, but if I need to learn some technical skills to make this happen, that’s fine as well.

I typically will create my own maps using a combination of the blank background and whatever tokens I can find for free online. For example, my most recent map had the players fighting on Avernus, so I started with a red background, overlaid tokens on the Map layer to create mountains, sketched in linework and hatching for Styx and the portion of the Basalt Citadel that they could interact with.

The overall map was something like 60×75 squares. As we’re playing the game at very high levels, I’m intent on making large scale maps to allow players that have abilities that improve their mobility to enjoy that.