CGTrader
02-19-2004, 10:58 AM
Hi,
I don't know maybe these are old tricks but anyway..
recently there was an interesting thread about shadow maps.
http://www.cgtalk.com/showthread.php?s=&threadid=120566&goto=nextoldest
Problems arise when we have a big scene and its not enough to have one big shadow map for every tiny detail. Multimediaman suggested an interesting technique making localized shadows. The workflow would be this:
for every object (or set of objects) in the scene you make a negative light and render from that light's orthogonal view (make sure you hide everything except these objects). This way you get an image of what that light sees. Take an alpha channel of that image and use it as projector map of that light and also exclude the objects from that light that were covered by that light. This way you can localize shadows for particular objects without using shadow maps and without affecting the illumination.
Thanks Multimediaman! :thumbsup:
There is also other technique that can do the same trick:
If you make light with intensity 0, shadow color - white and shadow desity -1, you will also get shadows without affecting an illumination and you can localize shadow maps to get better details. Only here you dont have to "bake" shadows for every object.
If you know other tricks about shadows it would be interesting to know.
I don't know maybe these are old tricks but anyway..
recently there was an interesting thread about shadow maps.
http://www.cgtalk.com/showthread.php?s=&threadid=120566&goto=nextoldest
Problems arise when we have a big scene and its not enough to have one big shadow map for every tiny detail. Multimediaman suggested an interesting technique making localized shadows. The workflow would be this:
for every object (or set of objects) in the scene you make a negative light and render from that light's orthogonal view (make sure you hide everything except these objects). This way you get an image of what that light sees. Take an alpha channel of that image and use it as projector map of that light and also exclude the objects from that light that were covered by that light. This way you can localize shadows for particular objects without using shadow maps and without affecting the illumination.
Thanks Multimediaman! :thumbsup:
There is also other technique that can do the same trick:
If you make light with intensity 0, shadow color - white and shadow desity -1, you will also get shadows without affecting an illumination and you can localize shadow maps to get better details. Only here you dont have to "bake" shadows for every object.
If you know other tricks about shadows it would be interesting to know.