I'm not sure GURPS' physics engine can handle this

[vitruvian]

Originally Posted by vierasmarius

If the character himself can shift between SM 0 and SM -10, it's not even an Affliction; he just has Shrinking with Affects Others. Don't forget Can Carry Objects if you want to shrink their equipment too.

Not if he can do it against their will, or have them shrink while he remains full-sized.

[vitruvian]

Originally Posted by Walrus

Don't mix up meta-trait and racial template. Meta-trait isn't directly appropriate as enhancement for Affliction and must be used either as racial template or divided onto elementary traits.

Compare turning every person into humanoid lulipute or frog or just shrinking them without morphology change.

Don't get confused between Afflicting Alternate Form and afflicting the underlying racial template or meta-trait. Neither the template nor the meta-trait can be afflicted directly, both are perfectly valid for Alternate Forms.

[vitruvian]

Originally Posted by jeff_wilson

I don't see that's necessarily the case when the metatrait does not specifically include human form, or any particular form.

It could be argued either way, I suppose. By a strict reading of Shapeshifting, the new template replaces rather than adds on to any existing racial template, so the elves should lose all their racial features, the buildings should lose IT: Homogenous and all the other traits that make them buildings rather than humans, and so on. Your individual traits add on to the template, though, giving odd results like a DF barbarian getting hit with an Affliction intended to turn him into a mouse (including -9 ST for 1 ST/HP in the template), and ending up being a slightly larger mouse with a ludicrous 8 ST.

That said, I don't think many GMs would have a problem with an Affliction (Alternate Form) where the Alternate Form basically consists of a Meta-trait like Body of Fire or Body of Air or some such, and doesn't change anything else. For SM, though, especially if you want the reduced ST, HP, movement, etc., you're better off Afflicting Shrinking instead.

[arconom]

Pretend for a moment that we don't care about the semantics of the build. How would that ability affect the game world? Someone fires a jet with range 10 from 3 yards away. What happens? Does the jet shrink and fall short?

[Gold & Appel Inc]

Originally Posted by arconom

Pretend for a moment that we don't care about the semantics of the build.

Hahahahahahahahahahahahahahahaha...

[David Johnston2]

Originally Posted by arconom

Pretend for a moment that we don't care about the semantics of the build. How would that ability affect the game world? Someone fires a jet with range 10 from 3 yards away. What happens? Does the jet shrink and fall short?

Probably. But there's a more fundamental issue. The ground beneath his feet. When this power first appeared it shrank with him. Suddenly he was standing on a tiny hemisphere in the middle of a large vacated bowl. It tipped over of course and he fell to the bottom of the bowl. Which then shrunk, putting him on a tiny hemisphere in the middle of a vacated bow that was twice as deep. And so on. And so on.

[arconom]

Originally Posted by David Johnston2

Probably. But there's a more fundamental issue. The ground beneath his feet. When this power first appeared it shrank with him. Suddenly he was standing on a tiny hemisphere in the middle of a large vacated bowl. It tipped over of course and he fell to the bottom of the bowl. Which then shrunk, putting him on a tiny hemisphere in the middle of a vacated bow that was twice as deep. And so on. And so on.

Now that we're on the same page...i think the ground would shrink to SM-10 below the character within the range of the effect.

[David Johnston2]

Originally Posted by arconom

Now that we're on the same page...i think the ground would shrink to SM-10 below the character within the range of the effect.

And I just described the problem with that. He tunnels to the center of the Earth.

[arconom]

Originally Posted by David Johnston2

And I just described the problem with that. He tunnels to the center of the Earth.

He wouldn't tunnel to the center of the earth. He only shrinks stuff to SM-10, so he would sink a bit and then be standing on micro ground in a hole. Its confusing. Think about what would happen if someone started pouring water into the hole.

[David Johnston2]

Originally Posted by arconom

He wouldn't tunnel to the center of the earth. He only shrinks stuff to SM-10, so he would sink a bit and then be standing on micro ground in a hole.

Every time the ground below him shrinks he moves down. Every time he moves down more ground below him shrinks. Sure, if the shrinking effect was a cylinder it would stop once all the ground below him is compacted down to the range of the effect, but it's not. It's a sphere, which means that he's always standing on a hemisphere with nothing to support it, so it tips over and dumps him on unshrunken ground, producing another hemisphere.

Although actually if he was using Affliction Shrinking, then there would be a maximum size the effect would alter so that objects all around him would shrink but the ground woudn't.

The effect you may be looking for could be produced by Control Space (only to increase distances) though. Everything would have to move farther to get anywhere an all attack ranges and perception ranges would be increased.