matching sky perspective to render perspective

[Dave Buckley]

when you guys are doing sky replacement, or adding more dramatic skies in photoshop, is there a way of knowing that the perspective in the the sky photograph matches the perspective of the render so that when they are composited together it looks natural??? what techniques do you incorporate to get this right, if you don't do it like this then how do you do it???

[mattclinch]

map a typically cloudy HDRi to the inside of a sphere centred on your camera that encompases your whole scene. should give you an idea of the sky distortion.

[Dave Buckley]

" centered on your camera "????

 

i was thinking more along the lines of doing it photoshop

[mattclinch]

you will struggle to do it in photoshop without a guide to tell you what is accurate... otherwise you're just doing it by eye. just knock out a scanline version of the HDRi map and drop it in in PS.

[Dave Buckley]

why use a scanline version???

[Dave Buckley]

and why hdri???

 

couldn't i just use some 360 degree sky bitmaps??

[mattclinch]

hdri because the tend to be spherical projection, but yes, any spercial projection bitmap will do. and scanline because it renders quickly.

[Dave Buckley]

ok cheers matt, do i not need to worry about lighting or anything on the scanline one???