Tim Hanson

Hi,

I have just tried experimenting with the lightscape TIFF-48bit HDR image format to convert it to a .pic (radiance) format for futher manipulation. It seems that Lightscape doesn't export the HDR information, and that the 24-bit RGB values are exactly the same as the 48-bit (no HDR imformation).

Can anyone confirm this and tell me if the physical values can be exported in the TIFF format from Lightscape, please?

Thanks,

Tim

marcdevon

Dear Tim

Yes, it is possible to convert a Lightscape rendering to the *.pic and *.hdr format. As you mentioned, you would save your rendering in a 48 bit tiff format. From there, use HDR Shop to convert it to an *.hdr or *.pic format. HDR Shop is free an can be downloaded at:

http://www.debevec.org/HDRShop/

One of the more useful features of HDR Shop is its exposure adjustment tools. Furthermore, you can use Reinhard HDR Tonemapping plugin to HDR Shop. This is a very powerful plugin that allows for you to do tonemapping. If you are not familiar with the concept of tonemapping, basically what it does is compresses the dynamic range of your scene. You may also use the PCOND program that is included with Radiance for tonemapping.

For these reasons, Lightscape's 48 bit tiff output still makes it one of the most capable render's available.


Marcus

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Marcus

Tim Hanson

Marcus,

Thanks for the response. Thing is, when I rendered the image as 48-bit TIFF from Lightscape and converted it to .pic using HDRShop, I used falscolor (radiance) to create an illuminance plot (falsecolor image). This was very flat in comparison to the original lightscape falsecolor. i.e. with same scale, it looked various shades of green from the .pic, but the lightscape falsecolor (for the same scale) had reds and blues i.e. the true dynamic range (numerical) did not translate through to the TIFF image.


If you don't agree with me and you can send me an example of one you've done, I would be very interested! Please email me at tim.hanson@arup.com if you would like me to send my example direct to you.

Thanks,

Tim

seismograph

just have a look at this tut :
http://www.cgtechniques.com/tutorials/lightscape.php


you have to render the ls image very dark to play around with the dynamic range.
Another drawback is the adaptive AA of lightscape since brighten the image over dynamic range let theAA fade away ..never again played with the AA params of LVS, but i'm sure there is a setting which let you calculate the AA on a fixed ratio.

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