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Straight Razor
ok need help with 4th ed spell mod

I'm wanting a variation of the levitate spell. I want a spell that reduces a weight of an object.
So i'm thinking that ti reduces the weight by [magic * (force + successes)]% and also reduces falling damage by (force + successes)

drain... i don't know


thoughts comments?
Dakka Dakka
Lightening the object would not necessarily decrease falling damage. Since the air drag would not significantly be reduced just by decreasing mass the object would not fall much slower. Also the resistance to outside forces may be reduced by the lack of mass. Rather than deforming the object it hit it is deformed itself.

Other spells with a variable effect are based on force*hits or hits. Dividing it by hits would be enough IMHO but more noticeable than your proposition.

Drain should be along the lines of turn to goo/petrify and shape [material] since those spells perform similarly drastic changes to the target of the spell.
Jaid
QUOTE (Dakka Dakka @ Sep 24 2009, 10:24 AM) *
Lightening the object would not necessarily decrease falling damage. Since the air drag would not significantly be reduced just by decreasing mass the object would not fall much slower. Also the resistance to outside forces may be reduced by the lack of mass. Rather than deforming the object it hit it is deformed itself.

Other spells with a variable effect are based on force*hits or hits. Dividing it by hits would be enough IMHO but more noticeable than your proposition.

Drain should be along the lines of turn to goo/petrify and shape [material] since those spells perform similarly drastic changes to the target of the spell.

a lighter object would possess less energy, even if it falls at the same speed. as such, reducing falling damage is not unreasonable.
Kitsu
It's specifically a restricted version of Levitate, right? How about reducing the drain code from Levitate by one or two?

That would put it at (F/2) or (F/2)-1 .

Considering that a real Levitate is only (F/2)+1, that might not be a fantastic deal, though. You could set it at (F/2)-1, and increase the effect to divide the weight by hits. Add the further restriction that it cannot be flung or otherwise moved telekinetically. Damage from falling would be reduced by Hits in effective meters fallen. Touch range casting only, and only affects one object or container of objects.

This could go out of control, with your mage lightening a car so the troll can pick it up and huck it, the mage having held an action to drop the spell while it's in midair. In that case, I'd make the object's Body, if it has one, the threshold of the spell, or set a maximum weight that can be affected at all the same as Levitate, 200kg per hit.

A more drastic version would be if you were using gravity control rather than telekinesis. I personally would not allow any sort of gravity manipulation for less than (F/2)+3.

All IMHO, of course.
Muspellsheimr
Edit: Nevermind, I don't want to get into this crap.


As for the spell, I would suggest simply having it at F÷2 - 1 Drain, & it reduces the effective weight of an object by Force x Net Hits kilograms. Resisted with Body (+ Counterspelling). Physical Manipulation, Line of Sight.
the_real_elwood
The force of an object due to gravity is the object's mass multiplied by the gravitational acceleration constant. A less massive object would experience less gravitational force, and hence it's terminal velocity would be slower because it requires less drag force to balance the gravitational force. Now, if you haven't reached terminal velocity yet, lowering the object's weight does nothing to acceleration.

And I think a "lighten" spell could be used to potentially reduce the encumbrance penalty a character gets from wearing too much armor.
DamienKnight
QUOTE (Kitsu @ Sep 24 2009, 08:07 PM) *
This could go out of control, with your mage lightening a car so the troll can pick it up and huck it, the mage having held an action to drop the spell while it's in midair. In that case, I'd make the object's Body, if it has one, the threshold of the spell, or set a maximum weight that can be affected at all the same as Levitate, 200kg per hit.


Weither it is light or heavy, the amount of force pushed against it does not change. A troll throwing a child and a troll throwing a boulder may still exert the same force. The kenetic energy of the flight would be greater with heavier objects, but as the Trolls maximum lift is reached, there are diminishing returns for the effort.

Either way, throwing a car and dropping the spell would not work, because the car would only have kenetic energy equal to its mass when thrown (light) x the force of the throw. When it gets greater weight, it would drop instantly towards the ground because the force of its flight would be insufficient to maintain its trajectory. It would be useful if you drop the spell just as the object is above the target, as Gravity would do all the work. By the way, you can do this with levitate if you like. Cast a force 5 levitate and you can lift 1000kg... thats 2200 pounds... the weight of many cars. You could levitate it above a person at a speed near to that of a thrown object, and drop the spell.



Also, I do not think that a percentage spell should be used. With percentages, a force one spell could be reducing weight on a gargantuan object.

Perhaps a spell just like Levitate (200kG per force) but it still reduced weight when it was incapable of neutralizing the entire weight of the spell, and which would not collapse when the weight is exceeded (as levitate does). This would be a spell with drain like levitate, only higher because it is a spell more robust and versatile than levitate.
Straight Razor
ok. think I'm going to go with the same drain as levitate and say it reduces object's weight by (force + net hits)*100Kg with the special note that nothing can be made truly weightless. spell doesn't break if object is heaver than effect of the spell. LOS sustained. resist with OR

I'm wanting to use this as an utility spell, not as some deranged trap making spell.
Karoline
QUOTE (DamienKnight @ Sep 25 2009, 04:16 PM) *
Weither it is light or heavy, the amount of force pushed against it does not change. A troll throwing a child and a troll throwing a boulder may still exert the same force. The kenetic energy of the flight would be greater with heavier objects, but as the Trolls maximum lift is reached, there are diminishing returns for the effort.

Either way, throwing a car and dropping the spell would not work, because the car would only have kenetic energy equal to its mass when thrown (light) x the force of the throw. When it gets greater weight, it would drop instantly towards the ground because the force of its flight would be insufficient to maintain its trajectory. It would be useful if you drop the spell just as the object is above the target, as Gravity would do all the work. By the way, you can do this with levitate if you like. Cast a force 5 levitate and you can lift 1000kg... thats 2200 pounds... the weight of many cars. You could levitate it above a person at a speed near to that of a thrown object, and drop the spell.


Well, normally I don't argue physics in the context of a game (much) but this is pure physics your talking about.

Object A of mass y is thrown at a speed of x.

Object A's mass suddenly doubles.

The laws of motion apply: An object in motion tends to remain in motion unless acted upon by a force.

No force was applied to Object A, and thus the fact that its mass suddenly changed would not affect its trajectory any (Mass is not a force)

Because all objects fall at the same speed regardless of mass (Ignoring air resistance which is negligible at low speeds) Object A would not fall any faster after gaining mass than it would have if its mass had remained constant.

Because Object A gained mass but kept the same size and shape, it would actually decelerate less as far as forward moment goes due to wind resistance, meaning it will go farther (Slightly) than it would have had mass remained constant.

So yes, you could make an object very light, have a troll throw it, and then make it heavy again and it would travel at a speed and distance similar to as if the object hadn't been made heavy again, but would still hit with the force of the heavy object being thrown at the speed of the light object.

Edit: It should be noted that changing the mass of an object as would be required in this example is physically impossible, but that has never stopped magic before smile.gif

Edit2: The main problem with your reasoning DK is that KE relies on Mass, not the other way around. You can change KE without changing Mass, but if you change Mass, you change KE.

Edit3: Oh, forgot to respond to the OP. I like the idea, but why not just use the rules for levitate, lower the drain by one, and just have it so the object can be made weightless, but can't be controlled via the spell like it can be through levitate?
Straight Razor
KE = 1/2 (M * (V * V))
M = KE / (V * V)
V = KE / (1/2 * M)

a gain in mass will reduce the objects velocity. a real world example of this would be to add mass to an already moving object of low friction. a boat or rail-car for example.

Now the real question would be to ask if the spell affects the objects mass or just gravities effect upon it. If i merely reduce gravity then mass stays the same and i can throw the car at you and it still hits as hard no matter how little it weighs.

::reply to above::
i want something that can do partial weight reductions, so that the spell will not break if the object to too heavy. but I'm not totally hung up on the idea. reducing falling damage and low drain were really my main to goals originally. i think i am trying to make a feather fall spell.
DamienKnight
QUOTE (Karoline @ Sep 25 2009, 10:17 PM) *
No force was applied to Object A, and thus the fact that its mass suddenly changed would not affect its trajectory any (Mass is not a force)


This would be true in space. We are discussing magic, which means we are speaking of staying within the gravitational pull of earth. When the mass increases suddenly, the force of gravity changes, pulling the object down sooner than if it had not increased in mass.
the_real_elwood
QUOTE (DamienKnight @ Sep 25 2009, 10:26 PM) *
This would be true in space. We are discussing magic, which means we are speaking of staying within the gravitational pull of earth. When the mass increases suddenly, the force of gravity changes, pulling the object down sooner than if it had not increased in mass.


Drop a bowling ball and a marble from the same height at the same time. Which one hits the ground first?

In a uniform gravitational field, objects accelerate downward at the same constant rate regardless of their mass. On earth, that rate of acceleration is 9.8 m/s^2.
Dakka Dakka
QUOTE (DamienKnight @ Sep 25 2009, 11:16 PM) *
Cast a force 5 levitate and you can lift 1000kg... thats 2200 pounds... the weight of many cars. You could levitate it above a person at a speed near to that of a thrown object, and drop the spell.
Actually you need at least force 6 and 6 or more hits on the spellcasting test to move the 1000kg. There is a threshold of 1 for each 200kg and fraction thereof. The maximum speed of the levitated object is force*net hits. If you manage that, you can drop the car on your enemies.
hobgoblin
why am i reminded of when someone summoned a whale in that other game, and used that to take out a target by the falling damage rules...
AndyZ
Someone may have mentioned this and I missed it, but I'd also allow for increasing jump distances.

Maybe multiply the distance of any jump made by the spell successes? Given that levitate lets you freaking fly, this doesn't seem unreasonable to me.

By this logic, you would divide the falling distance by the hits, keeping everything otherwise even.
Karoline
QUOTE (Straight Razor @ Sep 25 2009, 10:43 PM) *
KE = 1/2 (M * (V * V))
M = KE / (V * V)
V = KE / (1/2 * M)

a gain in mass will reduce the objects velocity. a real world example of this would be to add mass to an already moving object of low friction. a boat or rail-car for example.


Well, I'll ignore for a moment the fact that you adjusted the equation wrong. (Should be V = Sqrt(2 KE/M) not just 2 KE/M)

The real truth of the matter is that it is physically impossible to suddenly change the mass of an object, and so we can't really know if doing so would affect the KE or not. My assumption is based on the fact that the mass is still moving at the speed of the object, and thus the added mass gains KE as the mass is increased, while your assumption is based on the mass entering the object from a standing position, and thus having to overcome inertia.

Personally I like the idea that the lighten spell lowers the weight by making gravity affect it less smile.gif Can totally see the troll using a car as a battering ram biggrin.gif

Oh, and don't forget, it will make you be able to jump much higher as well smile.gif
Straight Razor
all this beside the point, but i'm enjoying the physics conversation/

QUOTE (the_real_elwood @ Sep 25 2009, 11:58 PM) *
Drop a bowling ball and a marble from the same height at the same time. Which one hits the ground first?

In a uniform gravitational field, objects accelerate downward at the same constant rate regardless of their mass. On earth, that rate of acceleration is 9.8 m/s^2.

true in a vacuum. wind resistance effects terminal velocity.

32 ft per sec. per sec. is falling not ballistic. i think were talking movement lateral to gravity.



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