shadows in shadows
Blitz3D Forums/Blitz3D Programming/shadows in shadows
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| just wondering for example if you have a lightsource,which casts a shadow from an object, say a sphere. If there is another object within the boundary of the spheres cast shadow, would that object cast a shadow also. or will the shadow be the same tone as the spheres shadow and therefore disappear. ideally the second shadow would be darker and there for be visible This is causing me problems when rendering lightmaps, because the secondary shadow is not visible. |
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| If there is another object within the boundary of the spheres cast shadow, would that object cast a shadow also. or will the shadow be the same tone as the spheres shadow and therefore disappear. Think about it logically - the shadow is cast because no light can pass through a solid object. Therefore how do you reason that an object with another object between it and its lightsource would cast a shadow?ideally the second shadow would be darker and there for be visible It won't. Stand outside your house on a sunny day, on the shadowy side. Do you see your shadow? :) |
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| he he i just never thought about it before. but the reason it worries me is that I have detailed structure , which lies within the shadow of a house and it looks as though it floating . part of the structure lies outside the houses shadow and it just looks looks odd graphically, even though as you say , light can't pass through solid objects. suppose in art its often what looks right and not what is correct. |
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| The only time you get shadows that overlap with different 'darknesses' is when you have more than 1 light source. |
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| yeah i was thnking that. I decided in the end to just move the lights aorund a little. works ok now |
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| BTW. in the real world out there you have Radiosity that could give you some kind of Shadow in the shadow nevertheless. |
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| "The only time you get shadows that overlap with different 'darknesses' is when you have more than 1 light source." Actually you can get overlapping shadows with a single light source if you're doing soft shadows. Soft shadow effects also occur when you treat a light source as being more than a point source (E.g. a large glowing thing). Note that you get soft edged shadows in real life EVEN FROM A POINT SOURCE. Oh yeah, and objects tend to have bright spots in the middle of their shadows (the so-called "Poisson spot" predicted by a physicist named Poisson who wished to ridicule Fresnel's theory of optics and later verified by experiment), but they're usually not visible to the naked eye. "BTW. in the real world out there you have Radiosity that could give you some kind of Shadow in the shadow nevertheless." Radiosity essentially treats any lit surface as a light source so, yes, you get the issues inherent in having multiple light sources. |
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| Radiosity is lightmapping that takes into account the fact that any surface light immuminates, it also bounces off of to some degree to illuminate other nearby surfaces. |
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| i could use a radiosity solution for my lightmap, but somehow the straightforward method looks a bit better on this particular model.The subtle effect produced by radiosity would be lost on my model. the lightmap would have to be huge to make it look good. might mess around with it a bit more though I also tried using area lights,which give you a nice shadow fade out but the lightmapper I am usng doesn't like them. |
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