1. Sound made by player should take into account all gear, and movement, and how the movement impacts the gear.
2. Sound penalty should drop at logarithmic rate over distance, not linear
3. The ambient light shining on both the detector and the target should be taken into account.
4. Sight-lines shouldn't have a visual limit, but "awareness" would increase according to proximity.
5. Carrying a lit torch should nerf or reduce the effectiveness of Invisibility / Chameleon
6. A spike in sound/penalties for whenever you draw a weapon or change gear
7. Other applicable skills should help off-set some of the penalties, such as Light Armor, Heavy Armor, etc.
8. Greater benefits for those who reach higher skill levels that make it worth the effort.
- extended back stab multipliers
- eventually counter or minimize penalties for sound
- counter movement speed penalties for sneaking.
Original Post follows with details and other ideas if you feel like wading through it.
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I'm currently working on a Mod for Oblivion to attempt to implement some of these ideas, and felt it might be worth posting in case you thought some of them were worth implementing in Skyrim.
It's complicated, but I will do my best to be brief.
OVERVIEW
In Oblivion, the main three categories that go into detecting are Sight, Sound, and Skill. Makes total sense. But here are some suggested alterations.
REVISING THE DETECTION DISTANCE FACTOR
In Oblivion, the exact same formula was applied to all three categories ( 1 - (distance between Detector and Target / Max Detection Distance) )
In order for things to be a little bit more immersive, and slightly more realistic, I'd have a totally different calculation for each category, as well as other tweaks to really flush it out.
SIGHT:
1. No max distance. In perfect lighting conditions and direct line of sight, a person can see a candle three miles away at night.
2. Instead, apply lighting conditions to both the target and the detector. If both are in the same lighting, and in LOS, and six feet apart, you are gonna see each other. However, if one is in a very bright light shaft (100 ambiens), and the other is nearby, but in a pocket of darkness (8 ambiens), you could make the argument that the one in the light would have a lot of difficulty seeing the one in the dark, even if they are six feet in front of them. We already run into that as players when we walk into a dungeon and light a torch, so the same should be applied to NPCs. Speaking of torches...
3. Torches and invisibility. I think that if a player has a lit torch out while being invisible, either the invisibility gets nerfed or the 100% effectiveness of the spell is offset by the brightness of the torch. So if a torch gave off 70 Ambiens, the invisibility would only have an effectiveness of 30. Same would apply to Chameleon, although the spell might not get nerfed, the effectiveness of the Chameleon is countered by the "floating torch" effect.
4. Weather. I am hoping that in addition to line of sight, lighting, and solid obstacles, you can also take into account things like glass, fog, water, etc. That'd be sweet.
5. Peripheral Vision. I think it would be swell to add peripheral vision into the equation, not just LOS or not LOS. One would get full bonus for LOS, about a 90 degree field of view, penalties for peripheral, about another 30-40 degrees to either side. Different races (like Argonians), might have a wider field of view, and therefore be harder to sneak up on. These would be bonuses purely towards detection, not just a bonus to their sneak skill.
SOUND:
1. Volume drops over distance exponentially, not linearly. I dabble in music/dj-ing, and have done quite a bit of research on the subject. This is an oversimplified explanation, but the way human hearing works, the perceived volume of a sound drops in half for every three feet it travels, until it eventually becomes inaudible. So the actual max distance is determined by the initial volume of the sound being made. The penalty would be the volume of the sound by the time it reaches the position of the detector. You could also layer in ambient noise, and how distracted they might be. When I play a thief, I usually move when two opponents are in a conversation with each other. Granted, that might be a real pain to program, so you could go with an alternate simpler algorithm that does set a fixed max distance, but calculates what the initial volume/penalty was, and what it falls off to at any given distance.
2. Volume of gear. I love Oblivion, but the idea that I could be in full heavy armor and run around in my barefeet while sneaking as a novice and not be heard was kinda silly. So my thought is you take into account all the gear that is equipped (clothes, armor, weapons out, etc.), and use the weight of it as a base, then make adjustments due to type (heavy/light/clothing/one handed/two handed/bow/staff). So Heavy Armor would make more noise than Light Armor, even if they are the same weight due to design. A longsword that is drawn has a greater chance of accidentally scraping a wall vs. a dagger that you can hold close to the chest. Plus the bigger the weapon is, the more "bulk" it adds. Try sneaking around with a Halberd out.
3. Effects of sneak mode. In sneak mode, you make further adjustments based on the skills the player has. For instance, someone with a high blade/sneak skill could offset the awkwardness of a longsword by deftly holding it so that it won't scraqe, or let the blade reflect any nearby light. Or a good armorer skill might imply the player knows how to "pad" the armor properly, and then the light armor/heavy armor skill indicates how well they know how to move in it, and then finally the sneak skill kicks in. However, even if you are maxed out in everything, heavy armor is still gonna make *some* noise. But then you can always counter that to some extent with an enchantment of some kind.
4. Magic effects. I always thought it would be neat if the silence spell had a positive spin to it: it nullifies any sound penalties. Granted you can't cast spells yourself, but if you are about to backstab someone, then it doesn't really matter then. That's the chance you take.
5. Running. Just like in Oblivion, there should be a sound penalty. But I'd make it higher to start, and then use Sneak and Acrobatics mastery to offset the penalty. If you are a Master in both, then I figure you are running like a Ninja, full speed, no penalties. That also means that the speed penalty for sneaking could/should be scaled to skill level as well. When you first start, sneaking is awkward, so you are forced to move slow. The better you get at it, the faster you can move without any increase in sound made.
6. Exterior vs. Interior. Initially I had trouble with why the max distance doubled, but I now I don't mind it. Out side there would be fewer obstacles because you would be in a larger space, so sound and visibility would extend further anyway.
7. Drawing weapons and changing gear. Now I know this is a bit over the top, but wouldn't it be neat if there was a sound penalty spike for the duration it would take for you to sheathe/draw a weapon or swap out pieces of armor? Set the penalty on a timer.
8. Race. Just like dogs have more sensitive ears, perhaps certain races/creatures do too, which would provide a multiplier for their ability to detect you (for better or worse). I'm thinking mainly the Khajiit in this case would be tough to sneak up on due to their hearing. These would be bonuses purely towards detection, not just a bonus to their sneak skill.
SKILL:
I actually like it pretty much the way it already is in Oblivion. The Sneak skill is a great "awareness" skill, and the further a target is from you, even if it is within your line of sight, you will be more likely to concentrate your attention on things that are closer. Along those lines, here are some other ideas to consider:
1. Distractions. If an NPC is in the middle of a conversation, or there are other NPCs around, they might be less likely to notice the player.
2. Fame/Infamy: I would say that the more fame/infamy you have, the more likely someone would spot you out of a crowd. There's nothing worse than trying to sneak up on someone from behind to pick a pocket and hearing a voice from behind *you*: "HEY! Aren't you the hero of Kvatch?"
3. Disposition: If people really like you, or really hate you, they would be more likely to pick you out of a crowd as well. Walk into any party, and see which people you notice first.
The best thieves are the ones that walked right past, and no one remembers what they looked like.
I've got ideas for adjustments for sleeping, swimming and jumping too, let alone tone and color of clothing worn, and extending sneak attack multipliers through all levels of Mastery, but I've already written more than I intended.
I really believe the suggested changes to the main three categories will not only add another layer of realism, but will really challenge a player to be a really good thief in the world of Tamriel. It won't be easy, but if they pursue it, at the higher skill levels, the rewards will be worth all the work.
I know these are significant changes, considering your deadline. But having been working through the math myself, I think a lot of the above features could be implemented without too much development time.
Thanks for listening.
And thanks for making such great games and reaching out to the community.
Saebel