SSE Is Negative Lighting possible?

[SamHe11]

I remember in the Oblivion construction kit, the Light object window had a box called "Negative" that, when checked, would cause your light source to absorb light from its radius rather than emit it. So it was like you could create your own placeable shadows. It was a cool trick. However, there is no such option in Skyrim's Creation Kit. So I'm wondering if there is still a way to do this with some combination of light object settings. I've played around a bit with some combinations of settings but haven't had much luck. Anyone else know of a way to do this? Edited June 3, 2021 by SamHe11

[SamHe11]

Thought I'd mention my findings in case anyone is interested. I don't think this has received much attention in the past as searches have come up basically fruitless. Been playing around off and on with this and I've gotten the effect I was looking for. The trick is to make a light object with Pulse effect. The key values to make this work are Fade, Period and Intensity Amplitude.

 

 

As defined on the Creation Kit's website:

 

Fade - The intensity of the base light object (higher = brighter). This isn't quite as important as the next two. It's more useful for just fine tuning.

 

Period - The time in seconds for the function (pulse of the light) to do a complete cycle. This is like the period of a clock's pendulum and how long it takes to make one complete back-and-forth swing. Or in this case, from full light intensity -> complete fade out -> back to full light intensity. As implied, this setting will be used to manipulate the length of time of this effect.

 

 

Intensity Amplitude (IA) - The amount the function (again, pulse of the light) can dim below the light's fade value. This is perhaps the most important of the 3 settings. An Intensity Amplitude that is greater than the Fade value will dip into "negative" lighting. It will literally start absorbing surrounding light up to the limit of it's radius, causing a shadow effect. The higher the IA, the darker your shadow will be. This also has an impact on overall length of time of the effect, as described below.

 

The thing to keep in mind here is that the relationship between Period and IA (and possibly Fade?) is proportional. Meaning, the higher the IA value, the longer it's going to draw out a full pulse cycle. Which makes sense. Remember the pendulum analogy? The longer the length of the pendulum, the greater the time it will take to complete it's period. I'm no math expert, but just through observation, I'd say it's somewhere in the ballpark of AI / Period = Total seconds of complete cycle. If you test this equation in the CK, you'll see in game that a 2/2 ratio will give you about a 1-2 second pulse, whereas a 10/2 ratio will result in about a 5 second pulse and so on. You can use the Fade setting as well as the light object's color to fine tune this further. With a higher Fade and brighter color, the time spent in darkness/light can be skewed more to the light side over the course of the pulse, meaning you'll have a shorter time in darkness and more time in light. With a lower Fade and darker color, you get the opposite effect. So if you want a more permanent shadow effect, use very low Fade value (0 will even work for more immediate effects) and a very dark shade of gray. Interestingly, Black will not work for the color. The game sees this as no light value at all and therefore won't apply any changes (kind of like nothing from nothing is still nothing).

 

I tested this out in game by equipping a helmet with an enchantment using GetLightLevel that posted a debug notification of the value every 3 seconds. Sure enough, it had an impact on the Player's Light Level value, meaning that this could be used as legitimate gameplay utility, not just for visual candy.

 

Unfortunately, going this route would imply that "negative" lights created this way aren't permanent. You just have to fudge around with the settings mentioned above to get the best shadow "intensity" per second that you need. This would best be implemented with things like Fire and Forget magic effects and other quick and dirty visuals. But play around with it and have fun. If anyone has seen this done in another mod in a better way, please let me know. Lighting is one of my favorite things to play around with.

Edited June 12, 2021 by SamHe11