My favourite maps are always set outdoors, usually at some prominant part of the day where shadows are king. Bright, bold sunlight in a map is something that can portray so much feeling. Looking at it today, boot_camp seems ugly, but I spent many mornings at home playing that map, simply because the sunligh in it typically matched the sunlight on those mornings. It made me feel like I was there, and added an aspect of realism that is otherwise hard to achieve.
So it’s hardly a surprise that all my major maps, Dust, Cobble and Aldea, have been set outdoors. There’s nothing more satisfying than mapping something out, setting up the sunlight, compiling it, running it in the game and actually feeling the heat of the sun and the coolness of shade. It’s one of the first things I try to achieve, because I know, if I can get that far, my eyes and brain are being decieved enough for the map not to look too artificial. The brain doesn’t just think “ooh, it’s a little bright, lets feel happy”, it considers how shadows are cast across structures too. The interaction between structures and lighting is what convinces the brain. If there is no interaction, that feeling isn’t there, and I know something isn’t right - maybe the design of the map is too artificial/out of scale/ugly or maybe I buggered the lighting up.
It’s because of this that sunlight is one of the main factors that affects my initial impressions of any outdoor map. Lots of amateur maps don’t get it quite right, and typically use sunlight as a method of lighting rather than a means to transfer atmosphere and feeling. These maps typically feel dull, grey and overcast - the sort of weather that is generally accepted as ‘rubbish’. For a player, their brain relates to real world weather and transfers the associated emotions, and hence the map becomes ‘rubbish’ too.
People like nice sunny days, generally. They also offer level designers some additional room to play - the most obvious example being light and shade. It’s fun, as a designer, to exploit the sunlight to create structures that players can use in a way they otherwise wouldn’t be able to if it were night time or a very, very dull day. Lots of ‘assasination’ type maps in a variety of games use this very mechanism - the target has to go out into daylight while snipers hide in shade.
HDR should make everything a little more fun. Players will have to account for the adjustment of their in-game retina, and it is this adjustment that will directly affect behaviour and short-term strategy (“I’ll wait here for a bit to adjust to the light before darting out into this street, unable to see threats”).
So kids, lesson of the day: use sunlight.