[Bf-funboard] Fake Area-Lights

Konrad Haenel public at konrad-haenel.de
Mon Aug 15 17:53:41 CEST 2005

Following a thread in the development-forum I'd like to add a small yet 
interesting proposal here:

The thread: http://www.blender.org/forum/viewtopic.php?t=6462

The proposal:

Fake area-lights using arrays of shadow-mapped spotlights

preface: Before area-lights became widely available it was a common 
technique to cluster an array of shadow-mapped spotlights to simulate 
soft-shadows. Though this method has clear limitations it works 
surprisingly well in many situations. At the same time it often greatly 
reduces rendering-time compared to real raytraced area-lights.

proposal: To improve workflow I propose that a new type of light should 
be made available: the fake-area-light. This would merely be a smart 
combination of features already available in blender. The idea is to 
make the process of creating and setting up a so-called "light-dome" as 
simple as creating an area light. The interface would offer direct 
access to the properties of such an object (actually spotlights 
dupliverted on some object, probably a slightly bent plane) and expose 
it as ONE object to the user.

details: The properties of the fake-area-light are pretty much the same 
as those of a spotlight, with the addition of the number of lights and 
the properties of the base-object on which those lights are mounted. 
Additional properties might prove useful, like different shadow-ranges 
for different spots of the fake-area-light. But these details may well 
be implemented later on.

final thoughts: I think implementing this should be pretty 
straightforward as it's mainly combining existing features in a better 
interface. In fact, this might even be possible using python-scripting, 
however a direct implementation would be more elegant IMHO. Judging from 
my personal experience this would be a feature greatly appreciated by 
animation-oriented artists for whom rendering-time is still one of the 
most crucial aspects of each project. Setting up light-domes is possible 
already but it's quite a tedious task and the resulting objects are not 
exactly nice in handling.

For nicer pictures,


PS: You can see the soft-shadow results of a light-dome on my 
Kneissl-Ski animation on my homepage. I tried real area-lights, too, but 
rendering-times were unacceptable.
link: http://www.konrad-haenel.de/projects/kneissl_powerglide/

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