What does one see, when he sees through a physical illusion?

Question

My character cast the physical mask spell.

Basically, this spell lets me look, sound and smell like I want (within reason). According to the spell's description, it affects all senses and cameras. As stated by the spell's name, it is the physical variant of the spell.

My character transformed into a person of the opposite gender and my GM said that my party members, which saw the spell being cast, can see through it. We had a short discussion regarding what they see, but we never came to a conclusion. I would like to know: What do people see when they can see through a physical Illusion.

• Do they see the real or the illusory looks?
• If they see the truth,
  • do they know that the caster actually looks different for people not seeing through the illusion?
  • do they know how the caster looks for people not seeing through the illusion?
• If they see the illusion,
  • do they know how the caster actually looks like?
  • do they hear the real or the illusory voice?

Answer 1

OK, did I grab the correct text here for Physical Mask? I think it is right but I am copying from the internet as I don't have my 5E book on hand and can't quote it perfectly off the top of my head. ;-)

Mask

Type: Mana • Target: 4 • Duration: Sustained • Drain: (Force/2)

The mask spell alters the target’s voice, scent and other physical characteristics. The target assumes a physical appearance (of the same basic size and shape), chosen by the caster. Observers can make a Resistance Test to attempt to overcome the illusion. Mask affects the minds of viewers.

Physical Mask

Type: Physcial • Target: 4 • Duration: S • Drain: (Force/2) +1

Physical Mask functions like Mask, except it affects technological sensors as well.

This is a greyish area that seems to cause house rules. The way that we have always done it is by looking at the rule and doing our best to make it make sense and then sticking with it unless we discover that it seems to have a game-breaking effect and then we re-evaluate... just like any house rule.

So for this one: Assuming that is the correct text, then that last sentence in the Mask description makes all the difference in the world. The physical description doesn't build on it other than to effectively say it is basically the same but also with technology. So... it affects the mind for people and the mind (CPU?) for technology.

For us that translates to illusion magic like in the real world. If a mage pulls a rabbit out of a hat and you see through it, then you can see how they did the trick. You still see what everyone else saw and you know what the people that were fully dazzled experienced, but you aren't fooled. If an android/camera/security system with AI/TV viewer at home is watching the same trick and they are fooled, it would either be the same way as with a TV viewer or effectively the same way as with an AI security system. Someone watching playback where the AI flagged it as an illusion would either see the actual person or the illusion and be able to toggle back and forth or whatever... but they could definitely see both what was there really and what supposed to appear to be there.

So for your example, with our house rule about this grey part of the rules: You are changing appearance and gender and your party members automatically know it is an illusion and so they can automatically see both what you intend and what is really there. Like watching the magician practice pulling the rabbit out the hat. Once they are good at it they still know how it is occurring and see the trick for what it is, but also can see the trick as it is intended to be seen.

But again, go with what you want as long as it keeps the game fun. If you want a house rule that says they need to roll to be able to get past the illusion then it wouldn't be far fetched for someone that failed to still "know" that it is you but "can't tell that it is you if they didn't already know it" effectively not seeing through it, even though they were there for it. It's magic that affects the mind and some minds react differently to the same input. After all, you can ask 5 different eye witnesses that were standing next to each other and get 5 different stories.

Answer 2

Physical Illusions: Physical illusion spells create actual images or alter physical properties, such as light or sound. Physical illusions can be used on both living and technological systems. They are resisted by Intuition + Logic; non-living devices resist with their Object Resistance. The magician must generate more hits than the observer for the illusion to be considered real. If the spell is not completely resisted, the target is fully affected by the illusion.

No houserule needed. They still see the illusion, they just know that it is fake.