Here's an interesting question that occurred to me recently - if you're using Shape-Shifting in a campaign, do you assume "Conservation of Mass" applies or not?

On the one hand, modern people tend to be very "scientific" thinkers - when given the option, most of us will assume things follow natural laws. Sure, magic can change that, but in the absence of magic, we'll tend to default to the scientific explanation. So, by that logic, we'd probably be left to assume that shape-shifting requires the shifter in question to either retain their natural mass, or have some means of "shunting" it elsewhere (or having a way to transform energy into mass and vice-versa, but that kind of energy release would be apocalyptic in scale if the shifter dropped even a few pounds - unless they had a means of shunting the energy away instead).

On the other hand, Chaosians ARE magic. Even ones who haven't traversed the Logrus or learned Sorcery clearly have the potential to do so. So, how do we know that they CAN'T "break the rules" and shift mass as well as shape?

We never really get an explanation whether or not mass is retained or not in the books. The closest we come is Merlin "shifting his mass downwards" to lower his center of gravity on the ice in Undershadow, but that's not the same as saying he HAD to maintain his mass (and besides, Merlin's been tainted by Shadow Earth thinking anyway). Jurt shape-shifted into a massive wolf - but considering that real-life wolves have been measured weighing as much as 180lbs, he could easily have retained all of his natural mass in the process. Merlin almost certainly increased in size when he shifted to fight Scrof, but did his mass increase as well? And while Chaosian demon-forms are almost certainly larger than normal human size, for all we know, their mass may remain the same.

Why does it matter? Well, unless we're playing a hyper-accurate-physics style game (involving calculates of mass and size to determine inertia and force), it probably doesn't. Still, it almost certainly comes into play when dealing with a shifter who wants to either shrink down to the size of a small bird/bat/rodent/etc, or grow to a massive and intimidating size (but potentially be blown over by a stiff breeze).

The DRPG blatantly says that mass must be retained (you can't add to or subtract from it), but then again, the DRPG says a lot of things that either aren't supported by canon at all or outright contradict it.

So... how do most people here think of Shape-Shifting, both in the context of the books, as well as in the context of the game?

I think there can be a little leeway in mass between forms. Say ~50 - 75 pounds, but not a huge difference. A full grown man shouldn't be able to shift into a blue jay. That's just too much of a difference in mass and size. It's illogical and makes my head hurt. I have made exceptions in the bird category if the bird is larger. But it's larger then your average example of the species and it's going to weigh at least 2x what the species usually weighs.

Yes, there's may be magic involved, but that makes me question how well or easy it is in an Amber where magic is non-existent, slow, or wonky. This isn't like being an animagus in Harry Potter.

I have the same feelings about Items. There is no way I agree with the idea that your magical horse, panther, dragon or whatever can morph into something small enough to hold in your hand unless that small item is heavy. I had a horse once that shifted into a motorcycle, but it was a hulk of a cycle and without the strength of an Amberite, my character couldn't have controlled the thing.

Even demon forms. Demon forms are rarely anything but significantly larger then a human form. But adding 50-75 pounds of muscle will make that form a hulk over your human form.

I insist on rough parity of mass and allow for 'hollow forms' that have mass stretched out over larger volume. Then depending on experience or teachers, I allow for absorbing and ejecting mass to really change that factor.

But I also include dangers for the unwary or tired shaper.

I always sort of used a 2/3rds rule, where you could sort of drop to about 2/3rds of your mass, or shift up to 3/2nds.

So, someone who was 100lbs human form could shift down to about 66lbs or up to around 150lbs. Someone who was 200lbs would have a range of 133-300lbs. And so on.

Hey

I know I'm dredging up an old conversation but I thought I'd add my 2c as it is a topic I relatively recently considered for my own campaign. SS can be considered in various ways from the idea of shadows lying for you (no SS at all but a simply a manipulation of shadow itself - who knows what a 'pure' Amberite looks like!) to you idea of a person being able to shift to literally anything in (as mentioned) a very Harry Potter way.

I personally looked at things from a game perspective. I needed a relatively 'unique' power for those not initiated to a major shadow editing power (thus not ruling out the shadow lying for you, a favourite of mine), which had prospects of improvement over time to 'better' things. With that in mind, allowing ever 'solid' (rather than purely magical) being in Shadow or Reality the option of being able to learn to control their form to some degree is an ability that is clearly unique when compared to pure sorcery etc.

Next is simply a way of limiting the 'simple' abilities so there is an obvious path of growth. Obvious limitations for SS are range of forms, personal choice to shift, size of form. partial shifting and period over which the shift remains I'm sure you can consider other limitations here but with each limitation you place on the power, you lower its value overall and increase the number of possible ways the power can be grown into.

As growth was expansion of capability was my focus, I therefore made it particularly clear that conservation of mass was one of the key elements of SS in my game (along with endurance drain for shifting etc) and we went from there.

So, while I've rambled, my answer is really that because I tend to play Amber as a game of overcoming limitations in all its various guises, that playing something like that so loosley will quickly overvalue the ability and plug too many holes too quickly.

Anyway, as I said, my 2c.
K

two thoughts -
"mass" as a concept would depend on the Shadow. Frex, in the real world, your mass increases as your speed increases. So I would expect Shadows where it is possible to shapeshift into planets, and others that don't allow any real mass change.

The character's Strength should limit effective size; for a character with human Strength any increase in weight would penalise their capabilities, even for ranked amber there would be a (fairly low) point beyond which any increase is detrimental.