hdri and physical scale

[SgWRX]

if you did want to use mr photographic exposure control and image based lighting, you still have to use the physical scale because chances are the hdri image might not be the same range as the mrsun/mrsky.

 

reason this came up is i'm still using some demo hdri's and applying them to old scenes. i remove all backgrounds, remove the mrsun/sky, add a skylight set to use the evnironment map, pop and hdri in the envrionment and use the IBL rendering mode with no exposure control. things seem a little dark and not as contrasty compared to the mrsun/sky, certainly there's no yellow tint either.

 

so in using mr photographic exp cntl, it just makes sense to use physical scale.

 

or am i doing something wrong?

 

thanks,

[thorsten hartmann]

hi

 

mr photographic exposure is ok. You must set on exposure Background. Here is a very good Tutorial about IBL +mr_sun. This works in mental ray and IRay!

 

http://www.rendergarden.org/en/blog/item/143-mixing-hdri-image-and-mr-physical-sky-as-environment-in-iray

 

mfg

hot chip

[SgWRX]

thanks. so in some respects we're still "playing" to get the desired results. yep that's a good tut, but so far i haven't combined the sun and ibl. will try that next looks really flexible though in terms of setting intensity of sunlight etc. i did play around with having a hdri image in the background and mrsun/mrsky without the mrphysical sky and that was nice too.

 

i really have to say that hdri lighting combined with saving out images as 32bit exr files gives an enormous amount of flexibility for exterior renders, i'm quite happy.

 

another interesting thing is that i took an old LDR cloud background i used to use and converted it to an HDRI image of sorts in Photoshop (by switching it to a 32bit image), added a sun disc like +12ev (with the paint brush tool and color picker) and tried that out and it worked great! so one thing i'm going to look at more is tweaking HDRI and/or creating HDRI's in Photoshop.