Linsen
Grand Master
Posts: 190
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Post by Linsen on Sept 26, 2005 6:29:05 GMT -5
I decided to open this new topic to keep the "Post your renders" section a little clearer. So, for starters, this thread is referring to this discussion. However, that is only supposed to be the starting point. Everybody who begins to think about lighting, will soon find out that it is one of the most complex fields of rendering. And even more important: Lighting can really make the difference between a standard not-so-spectacular scene and a really great one. So I'm hoping that this thread will bring our rendering efforts to a new level. So, here's the continuation of the discussion about my lighting problems: The first shot was rendered with indirect illumination turned on. I increased the samples in the "Image sampling" tab of the render menu to 4 and I used the Mitchel-Netravalli Image filter. Rendering time was round about 12(!) hours (yes, TWELVE). Unfortunately the result is still very grainy. And therefore it looks pretty crappy. The second shot was rendered with indirect illumination turned off and sample rate set to two. To get a rather light scene, I had to turn the brazil skylight on. All other settings were the same. As you can see it's a lot sharper but the lighting doesn't look as natural. One of the main problems with that setup is, that the windows of the cars turn out too dark, you can hardly see through them. But rendering time was only about 30 minutes. Shot 1: Shot 2: Once again a list of lights I used for this scene: 6 rather long and narrow reflection boxes 4 omnis 2 target spots 2 target direct lights
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Post by Bunta on Sept 26, 2005 6:45:27 GMT -5
Below are a few terms and defintions that may help the discussion progress with mutual understanding. Lights:Omni Light: Radiates light outwards in multiple directions, emanating from a single point. Skylight: Simulates diffuse outdoor lighting similar to natural light from the sky. Spotlight (target and free) :Illuminates an area within a cone, like a stage light does. Target Spots point at a target that you aim. Free Spots have no target, you can aim them where you wish. Directional Light:Uses a cone like a spotlight, but with parallel sides. Directional lights have parallel rays, spotlights have spreading rays. Shadows: Shadow Maps are the default shadow type for most lights. They give a soft edge to shadows. Shadow Maps are created by the Scanline Renderer. Area Shadows use anti aliasing to produce a softer atmospheric shadow.
Ray-Traced Shadows are calculated by tracing a ray from source to object. The default shadow for Sunlight Systems, Ray-traced Shadows have a sharper, precise edge. Good for buildings and man made objects. Render time will be increased undoubtedly. Advanced ray-Traced Shadows use less RAM as you render and make good use of anti-aliasing to soften the edges of your shadows. Source of information: 3DS MAX For Windows, Qantm source materials. Information is not reproduced in its entirety and has been altered and edited for simplicity. You will need to seek more detailed information if you require a step by step guide to such tools and operations as described above. How To Set Up A Render Farm click HERE to visit the tutorial.
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Looney
Advanced Skinner
Live For Speed - Bring it on!
Posts: 154
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Post by Looney on Sept 28, 2005 9:26:55 GMT -5
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Post by masrati on Nov 3, 2005 5:44:26 GMT -5
]. Area Shadows use anti aliasing to produce a softer atmospheric shadow.
Area Shadows have nothing more in common with anti-aliasing than any other shadow types, no matter of the renderer nor even the 3D software. Area shadows simulate the reallistic shadow from area light - which in fact are absolutely all realworld light sources. The reason why we don't wanna use area lights and area shadows in every situation is obviously the rendering time. Whenever the size of light source (radius of a sun disk, lenght of a light tube, size of a neon panel) is very small compared to the distance from the lit object, we can succesfully use the aproximation of the single point light and a simple sharp shadows. An example of this speed-up option can be Spotlight with raytraced shadows in 3ds max. Don't be fooled by "soft" shadow edge produced from Shadow Map - it's only the even futher simplification of the shadows generation. Shadow Map, as the name implies, is only the bitmap projection of the scene as seen from the light, with its pixel resolution limit. This bitmap is only roughly blurred which may mimic the real area shadow. But only true area shadows will showcase the important realistic detail where the shadow is as softer as further the shadow casting object gets from the surface where the shadow is cast. (try a horizontal plane, stick a high tower on it, add a sun and render with either kind of a shadow. don't forget to set a reasonable size of the area for area shadow, to see the effect). People who want to go a bit more in depth, should not be fooled by an extreme simplification. I believe in their intelligence. Try to understand or give up.
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