《HDRI美国城市光照贴图合辑》DOSCH HDRI USA City Backplates

本合辑是由DOSCH机构出品的HDRI光照贴图合辑2，大小：207MB，格式：hdr jpg。

HDRI拥有比普通RGB格式图像（仅8bit的亮度范围）更大的亮度范围。标准的RGB图像最大亮度是值是255/255/255，如果用这样的图像结合光能传递照明一个场景的话，即使是最亮的白色也不足以提供足够的照明来模拟真实世界中的情况，渲染结果看上去会平淡而缺乏对比，原因是这种图像文件将现实中的大范围的照明信息仅用一个8bit的RGB图像描述。 但是使用HDRI的话，相当于将太阳光的亮度值（比如6000%）加到光能传递计算以及反射的渲染中，得到的渲染结果也是人人素材非常真实和漂亮的。下面的两张渲染的图片可以看出使用HDRI后带来的巨大差异。

DOSCH HDRI USA City Backplates
Dosch HDRI: USA City Backplates contains 15 backplate sets or sceneries. Each set depicts one scene through backplate images, plus the corresponding HDRI for lighting of objects – and their reflections.
Through combination of the background image and an HDR-image of the object that is to be depicted at that exact location, absolutely realistic overall results are possible.

Background Backplate + 3D model of a product + HDRI for Reflections & Illumination = Perfect Result
The backplates are provided in a resolution of 7216 x 5412 pixel – and the highest resolution of the Spherical Map HDRIs is 13000 x 6500 pixel.
Radiosity – and therefore the use of HDRIs is directly supported in many 3D-applications like Lightwave (version 6.0 and higher), Softimage|XSI, Maya & Mentalray, Pixar
RenderMan, Bryce 6, Autodesk VIZ, messiah:render (Arnold), InSight (Integra), 3ds-max & VRay, 3ds-max & Brazil r/s (Splutterfish),
3ds-max & finalRender (Cebas), Cinema4D Version 8.1 and more. For further HDRI-rendering tools options the documentation of the used 3D-program should be consulted.
And each HDR image is provided in the industry standard .HDR. So they are useable in most rendering applications.

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