Transmogrifying Invisibility, What to do with it? Options

[Jebu]

The normal use for Invisibility is to get past people/cameras undetected. If it's used for that, problems rarely arise. There are things like hiding behind an invisible character, but I don't think that's a common problem. Invisible walls/doors are a much more serious problem, though. I haven't needed to handle invisible doors/walls myself, fortunately. I don't like the idea of Invisibility spell creating false images of objects that are behind the wall/door. I wouldn't mind if you cast Phantasm to create a false image of a doorway with door open, or without a door, but then the caster would have to know what really is behind the door, or just create any image he thinks would be appropriate.

As I said I haven't run into problems with Invisibility in my games, but if the players started casting it at objects, be it doors or walls or whatever, I think I'd house rule a modified version of the spell.

In the eye's retina, there's a blind spot where the optic nerve begins, there are no photoreceptor cells in that spot. But we almost never notice the blind spot, it's filled in by our brain, according to the surrounding area. Also because we have stereoscopic vision, the individual images from eyes overlap, filling in the blind spot if it's possible. You have probably seen the picture with two black dots, and when you close one eye and look from certain distance, the other dot disappears, it's where the blind spot is. Even then, there seems to be nothing odd in the picture, the brain fills the blind spot with the background colour, so it looks like a picture with only one dot. The other dot is invisible to you. Only because you know the dot should be there, you can see your brain was fooled.

Now, if I made a modified version of the Invisibility spell, I'd make it work like that. If the viewer does not resist the spell, it's like a blind spot for him. It's totally invisible unless you have other means to determine something should be there. This changes almost nothing when it's used to make people invisible. If he walks past a painting, the viewer's brain fills in the image his eyes see, and he doesn't notice anything. Only if he was specifically looking at the painting close enough, he could notice something odd. And if the invisible person didn't stop between the viewer and the painting (a stupid thing to do), the viewer would probably blink his eyes couple times, and shrug. Unless he was trained to look for anomalies like that to spot invisible intruders.

Now, when it comes to inanimate objects, this modified spell would be a lot worse than the original one. It couldn't be used at all to see through things, just to prevent people from seeing them. Which to me makes much more sense when the invisibility is an illusion and doesn't really make photons travel through the target. It wouldn't make much sense anymore casting it at doors, because people know where the doors should be and would quickly notice it. It would, however, still work if you wanted to make an assault rifle invisible to carry it around without raising suspicion.

In case the viewer notices something odd, I think he still shouldn't see the invisible thing if it's still sustained. If it's a door or other object he bumps into, or finds out about because he knows there should be something, he could close his eyes and feel for the handle, for example. If he looked straight at it, his brains would still try to fill in the image, and if the blind spot is a big one, he might feel like his eyes just couldn't focus on it. If it was a person walking past a painting for example, and he kept moving, the viewer would lose track of him very fast. He could quickly punch or shoot at the invisible person with less than +8 I think, and if the person would be stupid enough to stand still in front of the painting, the penalty would be quite low, the viewer could see a rough silhouette which makes aiming a lot easier than firing blind.

I see I poured out quite a bit of text. Oh well, if someone read through it all, comments are welcome. And keep in mind this isn't my interpretation of the original Invisibility, but a proposal for a modified substitute.

Edit: Heh, I just realized my signature is kind of appropriate for this thread. :P