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Resisting Magic and Evaluating Intelligence
Data Collected from Stratics on 3/6/2000, Archived by UO Renaissance

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Resisting Magic, by Rainman

Many people wonder exactly how to deal with resisting the powers of magery in UO. Many are confused as to exactly how things work, and what combination of skills they may or may not need to effectively combat the more powerful casting creatures, or mage player-characters. The intent with this document is to give the average player a firm grasp on exactly how resistance is calculated. The further you read along this document, the more the inner-workings of the game are "spoiled" for you.

Mini-Faq:

Question - Does Evaluate Intelligence help me resist spells?
Answer - No, Eval Int help mages only by rewarding them with extra damage (or penalizing them with less damage) depending on how their Evaluate Intelligence matches up with their opponent's Resistance skill. Eval Int is like Tactics for a Mage.

Question - Help, my character is a combination of a Mage and another profession, do I need Evaluate Intelligence?
Answer - That's a difficult decision. You need to consider your playstyle, as well as you character. If you rely on your magery to do a large portion of your combat damage for you, then chances are you should attempt to advance your E.I. skill. However, if you primarily use Magery to paralyze targets, poison them, curse them, recall away, or cast any other non-attack spell; then chances are you won't benefit from high evaluate intelligence.

Question - I've heard that Evaluate Intelligence can tell me how much mana a target has left, is this true?
Answer - That works if you have 76 or higher Evaluate Intelligence skill.

Question - Does resisting a spell compare my resistance to my attackers magery and evaluate intelligence skill?
Answer - No, it does not. Resisting a spell only compares your resistance with your attackers magery, and the circle of the spell being cast. (a full explanation is illustrated below)

Question - Why can't I ever resist anything that's cast at me, even magic arrow?
Answer - Remember that your resistance is figured in with the magery of the person casting at you. If your resistance is very low (below 40) then it becomes extremely difficult to resist almost anything cast by a master or grandmaster mage.

DIRECT DAMAGE SPELLS:


(Including: magic arrow, harm, fireball, lightning, energy bolt, explosion, chain lightning, meteor swarm, flamestrike, and Earthquake)

Here is an outline of how spell damage is calculated:

Actual_Damage_done = (Base_Spell_Damage - 50% [if Resisted]) + Eval_Intelligence_Damage_Modifier

Your chance to resist is calculated by comparing your resistance skill to the magery of your attacker, as well as the level of difficulty of the spell he/she is casting. This assures that it is always more difficult to resist a flamestrike than it is to resist a magic arrow, as the circle of the spell is included in the chance-to-resist calculation. It also gives clear advantages towards having higher levels of magery, as even fireball can become extremely deadly when it's being thrown from multiple master or grandmaster mages.

Figuring your chance to resist a spell is done as follows:
Your chance to resist a spell is the greater of either:

  • Your resistance skill divided by 5
    Your_Chance_to_Resist = Your_Resistance / 5
  • Your resistance skill minus the sum of (your attackers magery skill (less 20 points) divided by five) and (the circle of the spell multiplied by 5)
    Your_Chance_to_Resist = Your_Resistance - (( Attackers_Magery - 20 )/5 + Spell_Circle*5))

This ensures that you always have a minimum chance to resist a spell. That minimum chance is your resistance skill divided by five. So a character with 30 resistance skill, always has at least a 6% chance to resist ANY spell thrown by ANYONE. This is necessary to ensure that its still possible to advance the skill, even at low levels. Admittedly at zero skill, your chance to resist would be zero. However, you can easily train up to 20-30 points of the skill from mage NPC's (this is highly recommended to anyone who has a character with zero resistance).

Conversely, This tells mages that they don't always have to use the highest possible spell in their arsenal. If they know their opponent well enough to have a grasp of his/her resistance skill, lower spells can be used with nearly equal effectiveness. (though admittedly, at a higher cost in reagents). Your evaluate intelligence skill, as an attacker, does not enter in to this part of the equation. Quite simply, Evaluate Intelligence has no affect on your opponents chance to resist a spell.

IF A SPELL IS RESISTED, DAMAGE IS THEN REDUCED BY HALF
ALL remaning damage (resisted or otherwise) is affected by the relative amounts of your resistance skill versus the evaluate intelligence skill of your attacker. This is a passive check of the skill, the player does not need to use evaluate inteligence on anything during or before combat to gain the benefits of having high evaluate intelligence (EI).

The remaining damage is multiplied against a small equation:

If your resistance is higher than your opponents evaluate intelligence, then the equation is:
(1 + (Attackers_EI - Your_resistance) / 200 )

If your resistance is lower than your opponents evaluate intelligence, then the equation is:
(1 + (Attackers_EI - Your_resistance) / 500 )

From this modifier, further damage is either taken away or added to the Base_Damage after resistance was figured in. If the spell was resisted, then Base_Damage is already at 50% of what it would be, otherwise it's still at 100%.
Here's a small table Illustrating the effects of this modifier:

Extrapolated Damage Modification

These percentages are what happens to the damage after the spell is/is-not resisted.

 

Eval Int = Resist

100 EI vs 50 MR

100 EI vs 0 MR

50 EI vs 0 MR

0 EI vs 50 MR

0 EI vs 100 MR

50 EI vs 100 MR

Damage Change

No Change

+10%

+20%

+10%

-25%

-50%

-25%

Bear In Mind that these percentages are added or taken-away from the base_damage AFTER the spell is or is not resisted. Meaning that if your base damage has already been reduced by half(by resisting it), it can be reduced yet another 50% (if you have zero evaluate intelligence). This means that spell damage can be reduced by 50% twice, making the range for damage start from 25%, and spread all the way up to 120%.

Here are four EXAMPLE scenarios.:

Example One:
Attacker has 80 Magery and Evaluate Intelligence. He shoots an E-bolt at a defender with GM(100) Resistance.

Chance to resist = 100 - ( ( 80 - 20 ) / 5 + 6*5) = 58% chance to resist the spell
Damage modifier = 1 + (80 - 100)/200 = .9 = 90% of base damage (after resist calculation)

The result here is a 58% chance to resist the spell, doing 45% damage if resisted, and 90% damage if not resisted.


Example Two:
Attacker has 90 Magery and 70 Evaluate Intelligence. He shoots a flamestrike at a defender with GM(100) Resistance.

Chance to resist = 100 - ( ( 90 - 20 ) / 5 + 7*5) = 51% chance to resist the spell
Damage modifier = 1 + (70 - 100)/200 = .85 = 85% of base damage (after resist calculation)

The result here is a 51% chance to resist the spell, doing 35% damage if resisted, and 85% damage if not resisted.


Example Three:
Attacker has 95 Magery and 75 Evaluate Intelligence. He shoots an explosion at a defender with 70 Resistance.

Chance to resist = 70 - ( ( 95 - 20 ) / 5 + 6*5) = 25% chance to resist the spell
Damage modifier = 1 + (75 - 70)/500 = 1.01 = 101% of base damage (after resist calculation)

The result here is a 25% chance to resist the explosion spell, doing about 50.5% damage if resisted, and around 101% damage if not resisted.

Example Four:
Attacker has 100 Magery and 100 Evaluate Intelligence. He shoots a chain lightning at a defender with 30 Resistance.

Chance to resist = resist / 5 = 6% chance to resist the spell
(resist/5 is used because his chance to resist with the other equation is lower than his resistance skill divided by 5)
Damage modifier = 1 + (100 - 30)/500 = 1.14 = 114% of base damage (after resist calculation)

The result here is a 6% chance to resist the chain lightning, doing about 57% damage if resisted, and around 114% damage if not resisted.

Actual table of Raw Data collected from playing on Test Center

Left number is Evaluate Intelligence, (vs) the right number is Magic Resistance

 

0 vs 0

0 vs 50

0 vs 100

50 vs 0

50 vs 50

50 vs 100

100 vs 0

100 vs 50

100 vs 100

Average Spell Damages

Fireball

9.8

7.2

4.7

9.3

10.1

4.6

12.9

11.6

9.1

Lightning

12.7

11.5

4.8

16.4

12.9

6.6

14.1

12.9

10.4

Explosion

21.9

17.1

8.8

23.6

25.3

13.1

24.9

36.6

25.5

Ebolt

25.7

20.5

13

24.4

20.3

18.1

35.3

35.3

21.2

Flamestrike

26.6

22.1

13.6

29.5

28.3

21.5

37.5

30.3

29.2

Minimum Damages

Fireball

5

4

3

1

6

2

7

6

6

Lightning

5

4

3

6

6

2

7

6

1

Explosion

14

7

2

11

10

6

11

16

7

Ebolt

9

6

5

10

10

7

12

12

10

Flamestrike

11

13

4

13

12

12

21

13

12

Maximum Damages

Fireball

14

11

7

16

15

11

17

16

17

Lightning

20

16

10

23

21

12

25

26

21

Explosion

39

31

18

40

42

28

40

47

42

Ebolt

40

31

21

40

37

28

49

49

42

Flamestrike

37

33

24

47

49

37

59

54

49

Number of Resisted Spells

Fireball

0

0

5

0

0

8

0

0

5

Lightning

0

0

8

0

0

8

0

0

4

Explosion

0

0

7

0

0

6

0

0

5

Ebolt

0

0

2

0

0

6

0

0

4

Flamestrike

0

0

3

0

0

1

0

0

2

Credits: This raw data table was created in a labor of love by: Sir Adrick, Ledskof, Elowyn, Carisse, Abbi, and Faceless.
It was generously donated to the UOSS by Marduk of
RPG Bug Base

*Notes:

  • All mages had 100 magery, 100 meditation, and 100 int.
  • All victims had 100 str.
  • Each sample was of 15 spells, the victim's resist was reset to the testing level every 5 spells, so the testing procedure looked like this:
    1. Set to testing parameters (e.g. 100 eval int, 50 resist)
    2. Cast spell 5 times
    3. Reset to testing parameters (e.g. reset to 50 resist, in case skill was gained)
    4. Cast spell 5 times
    5. Reset to testing parameters
    6. Cast spell 5 times
    7. Set to new testing parameters


**Note: This data comes from Test Center, before the last changes to resistance became finalized.
As such, it's highly likely that small discrepancies exist between the equations and the data illustrated in this document.

NON-DIRECT-DAMAGE ATTACK SPELLS
Note all of this explained thus far does not cover the effects of duration spells that do not do "direct damage". Most of those are, at this point, unresistable in their numeric affects on your stats. However, higher resistance has proven to significantly reduce the duration of these spells. The numeric effects of these spells on stats are easily tabled for you here:

Duration spells.

Magery Level

 

10

20

30

40

50

60

70

80

90

100

Stat Change

± 1

± 2

± 3

± 4

± 5

± 6

± 7

± 8

± 9

± 10

*Note: Duration modification data is not available. However, The numeric affects these spells have on you are simple to calculate.

A Simple example of this would be casting CURSE on a monster or player. If your magery is 85, then you take -8 points away from that character in all three stat categories. Conversely, if you were to cast bless, you would add +8 stats to all three stat categories.

Various Notes:
The new function of the spell Poison
is a complete mystery at this point. It is known that higher levels of resistance reduce the level of poison received and seemingly the duration that it remains potent. However, the UOSS currently has no conclusive data to share on this spell.

The spells Mana Drain and Mana Vampire work slightly differently. The calculation for the chance-to-resist these two spells is known to be similar, if not identical to the calculation for direct damage spells. However, instead of reducing their effects by half, when these spells are resisted, they are completely resisted, having NO AFFECT on their target. When they are not resisted, they take a percentage of Mana OUT of their target's attributes. In the case of Mana Vampire, that mana is given to the attackers attributes. How this percentage of mana is calculated, noone seems to know. Observations seem to show that these spells can take as much as 65-75% to as little as 30% of the mana currently available to the defender.

The Mind Blast spell is another complete mystery. Originally this spell compared the INT of the attacker versus the INT of the defender, and the loser suffered severe damage. Now, it's rather unknown exactly how this spell works with resistance and evaluate intelligence, or even how much damage can be accomplished by using it.

The spells Earthquake, Chain Lightning, and Meteor Swarm all have an added wrinkle. The nature of these spells is that they are area affect spells. As such, anyone standing in the area of affect receives a portion of the damage. This means that using these spells against large groups is rather ineffective, as the damage sustained by any one target is very low. However, against 1-3 opponents, the results can be devastating if timed and targeted correctly.