sree.arun.kr, I don't want to add support for a new format, I want to replace the existing library that loads 3DS files by one I programmed myself, so it's easier to maintain. I'll look at the pivot feature and hopefully will fix the new 3DS loader.

If jpg can import as tif then why HDRI can't import.

You misunderstood my trick: Sweet Home 3D doesn't support TIFF, it's just able to read any file containing some data at JPEG format, even if its extension is .tif or anything different from .jpg or .jpeg.

I am very much interested to know current progress of yafaray code conversion.

Nothing.