How would you build this...

[Prince Baran]

A guy in my group wants to build a character who uses Illusions, but they can be solid and cause damage. If he whips up a gun, it shoots. If he makes a fire, it burns. If he summons a monster, it can fight. You get the point.

Any clues? I thought maybe Illusion with Linked Create and Damage, but it was crazy expensive.

[Saltcrow]

Oh, it'll probably be a linked Perception-ranged Damage effect, which would indeed be hellishly expensive. Create may or may not be required since the actual Damage part handles the real interaction between the two.

He can always make it as an Alternate Effect and describe the 'damaging illusions' as a descriptor.

So the array would look something like this:

Mirage Master: 32-points array, all dynamic- [37pp]
•true illusion: illusion 6 (all senses)
•damaging illusion: perception-ranged damage 10, variable descriptor 2 (anything created by illusion)
•illusion solidified: create 10, movable, precise, subtle (looks real)

You might even want to consider the Illusion Powers Profile, which is one of the top power profiles so far


edit: I went ahead and made everything Dynamic, meaning you can have true/damaging/solidified illusions of lower ranks at the same time if he so wishes.

[Doctor Devious]

A "solid illlusion" is basically a "thing": in which case, summon minion/create object sounds like what you want.
Illusion would just be in the descriptor.

[Greyman]

You could also consider placing a Resistable flaw on Create to allow someone to willfully penetrate its reality.

Shadow Conjuration: Create (Tangible Illusion); Resistable by Will, Selective; Precise, Subtle. 2 points + 2 points per rank.

You create tangible illusions that have all the appearance of true substance, and will even support weight et cetera, but can be willfully penetrated by anyone realising their true nature. Characters interacting with your shadow conjuration are allowed a Will resistance check to perceive the truth. Characters who fail the resistance check must continue interact with the shadow conjuration as though it were actually there. A change in circumstances will allow new resistance checks, perhaps with circumstantial bonus.

[King Snarf]

A Check Required modifier (Deception) might not be out of place either; if the target doesn't believe that it is what the illusionist says it is, it's not going to hurt them.

[Doctor Devious]

The idea that an illusion is solid unless it is interacting with has a mind that knows its only an illusion is rather tricky to maintain.

Examples:

An landslide starts, so the hero creates a barrier to stop the rocks hitting him. No will saves: rocks are stopped.
After the landslide, the hero creates an illusionary monster than clears all the rocks from the road. No will saves, rocks are moved.
An enemy attempts to hit the hero, who is wearing illusionary armor. If the attacker falls for the illusion, the hero has a bit of protection. If not, they don't.
An enemy throws a rock at the hero, who is wearing illusionary armor. The rock has no will, so does the armour work or not? How is it different to the landslide case? Were the landslide barrier shielding other people, would the awareness by any watching person (other than the hero) allow the landslide rocks through?
An illusion attempts to hit a foe. If the foe falls for the illusion, the then combat as normal. If not, then illusion is just ignored.
An illusion picks up a rock and throws it at a foe. The rock has no will, so gets moved. The rock is not illusionaray, so the foe gets hit/missed as normal.
Your team-mate is injured so you wrap an illusionary bandage on their arm. Does it block the bleeding or not?
And so on.

There is a consitant approach whereby the illusion is destroyed if anyone (other than the hero) percieves it and believes it to be an illusion, which would be a nightmare to play (certainly not in a team, as all your teammates know it isn't real).

[JDRook]

As you can see from the wide range of responses, there are a lot of possible ways to do this, depending on what effect you want the power to have.

The Illusion effect by itself only affects Perception, manipulating how things appear. Anything else requires another effect, and since all effects require descriptors that describe how they appear, you may not need the illusion effect at all unless you want to mess with perception. As Dr. D points out, anything that has real effects like Damage or Summon or Move Object doesn't necessarily need the Illusion effect

Using your examples, whipping up a gun "illusion" that works like a gun would be a Ranged Damage effect. It could shoot and damage like a gun, but you can say it never runs out of ammo and can't be disarmed or broken (the normal limits and complication of a real gun). Mechanically, this is identical to shooting beams out of your eyes, it just looks like a gun in action (different descriptors). Making fire would be Damage with different modifiers and descriptors on it.

Summoning a creature can be the Summon effect, but you can often make it out of something else if you only want your summoned creature to do a few things, or more precisely, have few effects. A "real" summon can work independently and be attacked and killed (unless you modify it a lot, which I find can be unnecessarily cheesy), or you could have a Move Object effect with Damaging that looks exactly like a creature which can attack and move heavy stuff as if it had Strength equal to MO rank but (like the gun above) can't be targeted for damage, although you essentially have to work it like a puppet from a distance.

Now the Illusion effect can still be used with these powers, depending on how you want it to work. The basic descriptor for each power would make them look like guns and monsters, but deceiving opponents into believing they are real is another matter, otherwise you basically have something like the Green Lantern ring which can make stuff that effects the world but has an obvious source. Linking Illusion to the effects would make it more difficult for opponents to disbelieve, so instead of attacks simply going through the creature or gun and giving away the trick, the Illusion responds logically (creature seems to bleeds but doesn't slow down, gun seems to shift away from disarm attack) so the opponent may be fooled into wasting effort on treating the illusions as real.

The trick is making the effects look like they come from the illusions, but even if opponents see through that, the effects still happen. Saltcrow's array above would give you all of that (although you'd have to add in the Move Object), allowing for real effect with a coat of Illusion paint, so to speak.

Greyman and King Snarf's suggestions sort of work in the opposite direction, where the opponent has to believe in the power (ie fail resistance by Will or Insight) for it to work. This can be purely psychological or a particular style of magic or something else, depending on your game. These powers can be cheaper, since they are Flawed, but as Dr. D points out, they shouldn't have any effect on inanimate objects that don't have minds.

It really depends on how you and your player want it to work (and not work), so be specific. I'm no mind-reader, but I suspect they want the real effects with a dash of Illusion. I also suspect they don't want to Create stuff, just get the effects that stuff would make, so this would be my suggestion for a build:

Mirage Master: 50-points array, all dynamic- [53pp]
•True Illusion: Illusion 10 (all senses)
•Real Effects: Perception-ranged Damaging Move Object 12, variable descriptor 2 (anything created by illusion)

Similar to Saltcrow's, it's a relative simple and very powerful Dynamic array. Because it's Dynamic, the more powerful you make the effects, the less deceptive the Illusion can be. For instance, you could evoke a tank illusion that shoots with the power of a tank (Damage 10), but once engaged it can be seen through it with a DC11 Insight check. Whipping up a heavy pistol (Damage 4) would have opponents believe it's real unless they make a DC16 Insight check. The damage still works if it hits, though.

[Prince Baran]

JD, wow...truly wow. That was an amazing breakdown. Can Illusion exceed PL caps? i.e. - Illusion 15 in a PL 10 game. Also, does damaging Move Object function like bullets/fists etc. ? Do I need to put in a perception damage in to simulate other damage effects?

Thanks again for an amazing explanation.

Edit - I think this is correct.

[JDRook]

Rather than answer that one myself, I'm going to quote the Illusion Power Profile directly. If you have all these questions about Illusion powers, I highly recommend it.

Note that because the effect allows an Insight resistance check, Illusion’s rank is limited by power level like any other resisted effect (this is also important for Illusion Resisted by Will.) However, given that the power level limit on an Insight skill bonus is PL+10, the GM may choose to modify the power level limit for Illusion effects based on how the effect is used.

To expand on that, the Illusion effect is also a Perception Range Area effect by default, requiring no attack roll and evoking a resistance check. All Perception and Area effects are limited to PL, so Illusion would definitely be limited; the Dynamic Array I described would actually need to be PL12 because I made Move Object Perception and Damaging.

The resistance is unusual though. Most effects are resisted by traits that are PL-balanced; Defenses/Toughness and Fort/Will are the most common and each pair is limited to 2xPL, but the average resistance will still be PL. For instance, a PL10 PC could have Fort 8 and Will 12, making him more resistant to Will attacks but more susceptible to Fort attacks, so it balances out. Illusion is resisted by Insight, though, and as a skill it is allowable for a PL10 skill to be bought up to +20, which would make resisting Illusion effects very easy to the point of practically being immune to a rank 10 Illusion. Because of this, a GM might allow standard Illusions to be a higher rank than PL, although I wouldn't recommend this unless most of the PCs were buying up their Insight to high levels, and even then not more than PL+5. (Then again, if all of your PCs are buying that much Insight, you may have other issues with your game.) If you change the resistance to Will, this problem goes away, and Illusion is fine at PL for a maximum.

[JDRook]

Also, does damaging Move Object function like bullets/fists etc. ? Do I need to put in a perception damage in to simulate other damage effects?

Damage is Damage, the rest is delivery and descriptor. The build I had above had Variable Descriptor 2 which is 2 ranks of a 1p flat extra, and it allows the Damage to vary its descriptor within a broad set, which I defined as "anything the Illusion simulates." That is how the Damage can behave like bullet or fists or tank rounds or fire or lightning or whatever.

To be clear, it's actually Move Object with the Damaging Extra, but that Extra is basically identical to the Damage effect. I used MO + Dmg instead of just Damage to allow the Illusion to do things like grab or carry things or otherwise impose force.

I see you've added a few more extras. Indirect 4 is good, as is Subtle 2, although you could decide to trim ranks. You could also opt to affect fewer senses to save some points. And yes, that build would be PL12; you'd have to drop both Illusion and MO+D to 10 for a PL10 game. Alternatively you could drop Perception on MO+D and use regular Ranged, but then you'd need an attack roll, and the range penalty would be based on how far your caster is from the target, not the Illusion.