CoronaSun Link To HDR

[kahein]

Hi,
How can we link the rotation and angle of corona sun with wireparameter to the bitmap U and V offset.
I try to do it with the same method wich work with vray but with corona it doenst

[Ondra]

you mean standalone sun or the sun in daylight system?

[kahein]

stand alone sun

[Ondra]

its parameters are exported to maxscript, co it should be possible to do with some light scripting ;)

[Ludvik Koutny]

Actually it should be simply doable via wire parameter thingy :)

[kahein]

I link the sun rotation and sund height to u and v offset of bitmap but it just dont work

[kahein]

it stange because when i try with a simple box ( wire posX and posZ ) on the sun rotation and height, it work

[AnubisMe]

Try this http://www.peterguthrie.net/blog/2010/04/vraysun-and-hdri-sky-tutorial

[romullus]

I watched this tutorial out of curiosity and was shocked by such stupid inconvenient method of matching direct light with background image. I wonder, should i make video, showing a proper way of doing that. I may even include quick "wiring corona sun to hdri" example.

[kahein]

if you can do it please it would be very helpful

[romullus]

Youtube still processing it, but in a while, link should be ok.

[fellazb]

Thanks for the tutorial very straight forward solution you got there.

One thing is bugging me though, why do you really need a corona sun if your HDRI can also provide good shadowcasting? An anwser could be that a lot of HDRI's aren't good enough to produce sufficient shadows, but seeing this tutorial: http://www.ronenbekerman.com/hdr-image-based-lighting-3d-scene-setup/ you can tweak the HDRI to produce these shadows.

So then again, what's the benefit of using a corona sun when an HDRI can do GI and shadowcasting?

[romullus]

Actually i almost never do the way i showed in my tutorial, because i have most of hdri's tweaked in photoshop :] I've learned this technique from Christian's Bloch's "HDRI Handbook". Excellent lecture, i might say: http://www.hdrlabs.com/book/index.html
However it has adventages, as well as disadvantages compare it to direct light method.

Btw, guy in that tutorial on ronenbakerman.com, has painted waaay to big sun.

[Ondra]

How big? If i remember correctly, the real size comes out at about 1 pixel for 1k map :D

[romullus]

Well, sun's angular diameter is about 0.5 degree. So for 10000x5000 pano, it would be ~14px.

Edit: btw, i compared it vs corona sun once and it matched perfectly :]