I thought I'd try to put this race together but I'm going to need some help with the scripting bit.
http://www.gamesas.com/index.php?/topic/1085366-reqzwipzanticipation-of-shadow/ is a link with what I had in mind if you're curious.
Otherwise, let's start with the basics.
1. A way to identify interiors: http://cs.elderscrolls.com/constwiki/index.php/IsInInterior looks like it would do the trick. Alternatives would be OBSE GetParentWorldspace and GetCurrentRegions. Both of them "generally" return 0 from interior cells and I'm not sure if they're more reliable than the former.
2. A way to identify clear weather.
This one is trickier because I want to keep it compatible with weather mods and I assume each has it's own weather references. However, I could use OBSE GetWeatherSunGlare and GetWeatherSunDamage. GetWeatherClassification may be the easier way to go.
3. A way to identify light.
What do you think the most accurate way to check for daytime/nighttime would be? It shouldn't be a specific game hour but rather the time when it gets dark/light. I was thinking of using OBSE GetClimateSunrise/GetClimateSunset and comparing those with the GameHour variable.
Alternatively, I could use OBSE GetActorLightAmount along with a check for interior - if she's outside and the value returned by the function is above a certain value, then she's exposed to the sun. I don't know how the values scale though - what's the rough value GetActorLightAmount returns in clear weather as opposed to Rain?
I'll get to the shaders later. For now I'd appreciate any comments on this "battleplan" - other functions or ways of going about it.
Cheers!
cc