Spell Learning and Spell Failure Chances

[Uncle Al]

More gems from Silicoid's code dive - big thanks to him and Google Translate for making this stuff readable!

Google Translate is sometimes hilarious though - it helps to figure out it's translating 'Character' as 'Persian' for some reason. The best so far was 'Blunderbuss' which get's translated as 'indiscreet kiss'. Translate is obviously splitting the word into blunder and buss, but it gave me a chuckle.

A summary of Silicoid's post:

You get skill checks equal to level multiplied by the power level you try and cast at. Nothing else matters. So low mana cost, high level spells are very good for skill training. Success or failure of the cast doesn't matter.

Combat only spells are pretty straightforward, you make the cast and you get the skill checks.

Buffs, heals and utility spells work in three different ways -

1) Cures, heals etc. They earn a skill up if they actually could achieve something, so the target has to be damaged for heal, have a status condition for cure etc. Stamina is special in that the target must be tired but also it only gains skill ups in combat, everything else gains skill in or out of battle. I don't know about rest all, should test that some time.

2) Non combat utilities like Light, X-ray or Chameleon. You can only gain skill checks once every 3 minutes of real time. Casting before 3 minutes are up resets the timer so you get no skill checks but have to wait another 3 minutes. Casting in combat doesn't make a difference. Oh, loading a game clears the timer, as we already know.

3) Long duration buff spells that have a combat effect, like Missile shield and Armour Plate. These follow the 3 minute rule but also can earn skill checks on a cast if you cast the spell in combat and the new spell duration is more than four times the existing spell duration.

It doesn't count as combat unless you have active enemies, so initiating combat with no enemies around doesn't let you train skills. Equally if a spell goes off after the last enemy is defeated, it doesn't earn skill ups.

Spell failure chances:

Dark green - Automatic success
Light green - 1-5% failure, no fumbles
Yellow- 6 -15% failure, may fumble
Orange - 16 -40% failure, may fumble
Red - 41%+ failure, may fumble

If a fumble can occur, one third of failures will be fumbles.

The original post is translated below:


Refinement on skills spell casting:

Shadow Hound, Chameleon, Detect Secrets, X-Ray, Light, Hypnotic Lure, Sonic Boom,
Missile Shield, Armorplate, Enchanted Blade, Magic Screen

- Within three minutes of real time counting from the last casting skills will not occur
- Each caste sets the three-minute timer back to the starting position
- The first casting counting from the last save game is free (one for each type of spell for each character)

Features
------------- -------------------
Shadow Hound - does not cast in battle;
Chameleon - does not cast in battle;
Detect Secrets - in combat yu is not casting
X-Ray - in battle is not casting
--------------------------------
Light - in battle, the same rules as outside of battle
------- -------------------------
Hypnotic Lure - always grows in battle if at the time of casting the number of opponents is not equal to 0
Sonic Boom - grows in battle always if the time of casting the number of opponents is not equal to 0

There are situations when all opponents are killed, and only the move has reached the Persian and he still
conjures a spell when there is no one left, in this case the skill does not grow.

--------------------------------
Missile Shield - special growth in battle (see below)
Armorplate - special growth in battle (see below)
Enchanted Blade - special growth in battle (see below)
Magic Screen - special growth in battle (see below)

Special growth in battle:

IF (TD / CD) <0.25 TO growth_performance_allowed

TD - current spell duration (how much is left before expiration)
KD - spellable spell duration (spell_ strength * base_ duration)

Example:
Magic Screen - base duration 31

Assume at that moment in Magic Screen with 50 moves left

- if you cast Magic Screen of the 1st level (duration 31), then the coefficient will be 50/31 = 1.61 (the skill will not grow)
- If you cast Magic Screen of 7th level (duration 217) , then the coefficient will be 50/217 = 0.23 (the skill will grow)

============================== =====================
===============

The program for calculating the chances of success of casting a spell:
http://silicoid.pisem.net/CalcMagicChance.zip (251.49k)

There is no sense in giving a full calculation formula, it is still complicated and incomprehensible.
I will
give general conclusions: - casting of a spell is characterized by: A chance to fail and Chance to reflect
- The chance to fail depends on:
a) School skill
b) Elemental skill
c) Persian levels - for multiclasses, the sum of the levels for those professions that have this spell
d) The spell level
e) The base mana cost per unit of power - the figure next to the name of the spell on the sun list ex spell

- The chance to reflect is 1/3 of the chance to fail
- The chance to reflect is calculated if the chance to fail is 5%
- Reflection of the spell occurs only if the spell is failed

Color gradation:
Dark green - chance to fail: 0%, no reflection
Light green - chance to fail: 1% -5%, no reflections
Yellow- chance to fail: 6% -15%, there is reflection
Orange - chance to fail: 16% -40%, there is reflection
Red - chance to fail more than 40%, there is reflection

[Vic Asmadi]

Originally posted by Uncle Al:

It doesn't count as combat unless you have active enemies, so initiating combat with no enemies around doesn't let you train skills. Equally if a spell goes off after the last enemy is defeated, it doesn't earn skill ups.

From my experience, this is not always true. I can train with the Stamina spell by initiating combat any time, even with no enemies around.

[mpnorman10]

Originally posted by Uncle Al:

Silicoid writing: "There is no sense in giving a full calculation formula, it is still complicated and incomprehensible"

Silicoid's work is a wonderful thing he has given us, but he sometimes backed away from giving the full details of complicated formulas, which deepens my admiration and appreciation for current efforts to uncover the full and complete formulas in all of their complicated glory. Any complicated formula can be broken down into parts which are individually manageable. To know what the formula depends upon helps a little, but knowing exactly how the factor impacts the chances and the relative strength and any threshold levels of various factors exactly as applied is what is most valuable.

There are a lot of key facts in what you have presented here, such as spell failure and backfire chances, the 3 minute rule and other conditions that must be met for spell increase. Thank you for translating, distilling and delineating that info.

[CeterumCenseo]

Peddroelm's logging provides exact information (from what I can judge), what has a chance to increase skill and what hasn't. I found a few unexpected things and some confirmed, where there has been debate now for almost 2 decades now.

The version I have from him is quite perfect in this respect, I would say.

[Zergs]

Does anyone know what:

Hypnotic Lure - always grows in battle if at the time of casting the number of opponents is not equal to 0
Sonic Boom - grows in battle always if the time of casting the number of opponents is not equal to 0

means? Are hypnotic lure and sonic boom more efficient for training than say, Slow and Silence on the Arnika rogues?

[mpnorman10]

By "grow" he is saying there is a chance for skill increase and is further saying that that chance of growing will happen every time during battle if there are opponents and the spell is cast. I have not verified this but that is what it means.