iRay rendering Environment domes using the mirror ball trick

mCasual

Chasm iRay rendered using the mirror ball trick

i'll eventually post a tutorial on my site 

you create a sphere in daz studio 4.8
apply a polished aluminum shader ( mirror )
render this ball from above looking down
repeat with a camera below the ball and looking up

note that you must not render the whole half-a-ball, so you must figure how to frame at the horizon line
( i rendered the whole hemisphere then cropped at 0.707 of the image size, i'll get the pixel-perfect equation  in my tutorial )

then use the program Luminance HDR qtpfsgui.sourceforge.net/
or PanoTools etc

to Transform-Project the 2 images, mirror-ball to cylindrical 
( maybe that's not the correct destination format but it seems to work )

then use a paint program to assemble the two halves

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for the beach scene i used this method

create a sphere / diameter 1cm / divisions 64 / sides 128 / position ( 0, 150, 0 )
select the sphere / Go in the Surfaces tab / Select the "Default" surface of the sphere
apply the shader / My DAZ 3D Library / Shader Presets / Iray / DAZ Uber /  Metal Aluminum Polished
change the Base color to full bright white ( 1.0, 1.0, 1.0 )

Render Settings : Square image, ex : 4000x4000
Render Settings : Environment / Draw Dome / ON
Render Settings : Environment / Environment map / Strength: 1.0 (instead of 2 )
i'm not sure but i think increasing "Environment Lighting Resolution" may improve the results
Render Settings : Environment / Environment map i changed the image to an equirectangular image from www.hdrlabs.com/sibl/archive.h…

create a camera / position ( 0, 157, 0 ) rotation ( -90, 0, 0 )
Select the camera, Parameters tab / Camera settings / Adjust the Focal length until the ball fills the screen ( 233mm )

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for the bottom hemisphere renders, 
the camera is at ( 0, .1, 0 ) 
the camera rotations are ( 0, 90, 0 )
adjust the Focal length until the ball fills the screen ( 233mm )
note: if the camera is below ground level, and the iRay ground is ON, the iRay ground will block the view ! that's why we used yPosition = 0.1

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this image shows that we must not render the whole surface of the mirror ball in order to get the hemisphere 

 

and here you can see the settings i used to transform from the mirror-ball to the cylindrical format

 

 

then i save the image in tif format,

it's an HDR tif i think

my Paintshop pro 5 couldnt open it

when i convert it to png using imagemagick/convert ... it looks a bit dark

but all those issues will be dealt with ... later later later :)

but maybe before xmas

 

 

grinch2901

So the result is an image you can use as a backdrop on a sphere or an HDRI?

mCasual

if using Daz Studio iRay the image can be applied as the "environment" setting 

if you want to make it visible you set "Draw Dome" On

 

in Daz Studio 3Delight there's Uber Environment lighting that can use this

 

in Blender , in "World " it can be used as an Environment Texture

 

it's more like IBL image based lighting, but maybe if you can render it at different "expositions" you can build true HDRI using

 

also note that this type of image can be applied to a Daz Studio Primitive-Sphere and you get a sky-dome

on my site there's special Spheres that may work in some situations where the Daz Studio Primitive-Spheres dont

https://sites.google.com/site/mcasualsdazscripts5/mcjskysphere

https://sites.google.com/site/mcasualsdazscripts2/june

https://sites.google.com/site/mcasualsdazscripts4/spherical

https://sites.google.com/site/mcasualsdazscripts5/mcjsphericalcam

Click Here for a VIDEO

 

 

grinch2901 said:

 

So the result is an image you can use as a backdrop on a sphere or an HDRI?