Blending HDRI and Sky?

thomthom · 5 Jan 2012, 09:40

hmm.... if you use a plain colour for GI you can also easily tint the general environment while have full control over your sky shadow.

I made the sky size 20 so I got quite soft shadows - like on a partially clouded sky which my BG HDRI display. And then I lowered the intensity and now the shadow areas aren't so dark. Perfect!

andybot · 5 Jan 2012, 09:56

Well, the issue is with reflections. I went back to the original model I was testing, and it was an issue of reflections, not lighting levels. If your background is too bright or too dark, you won't see the reflection of your environment map, or you might see too much. The blend helps control reflections only. Hope that is of some use.

thomthom · 5 Jan 2012, 10:05

I'm not seeing any problems with reflections. It appears to me that I see just the BG HDRI...

andybot · 5 Jan 2012, 10:07

OK. I was just explaining the reason behind my alternative approach. YMMV
the illumination levels still depend on the sun intensity setting and HDRI multiplier either way.

thomthom · 5 Jan 2012, 10:10

I guess it might depend on the Sky and HDRI settings - in my current setup it seems to work ok.

valerostudio · 6 Jan 2012, 15:01

It all comes down to workflow and what you are trying to achieve. I use Fernando's method and wait patiently for Sky Dome!

ali64risk · 29 Jan 2012, 05:59

hi everyone
I chose a picture for BG in vray option window
does anybody knows how i can reduce the size of image and make it repeat in the back ground?

chon · 30 Jan 2012, 07:52

Hello,

in the Texture Editor of BG settings, if you use a TexBitmap, in the UVWGenEnvironment, you've got a "repeat" option for horizontal and vertical settings.

ali64risk · 31 Jan 2012, 07:36

@chon said:

in the Texture Editor "repeat" option

yes but it is not working for me:
it is a reflect able sphere I rendered for you to see
I attached original picture and rendered pictures with 1, 5 ,20 and 100 repeat both in horizontal and vertical directions.
as you see when repeat number increases it seams picture goes to be zoomed more and more in the background!
why I can not see at least one picture in complete size in the background? while I want to see pictures tiled in the background!

andybot · 31 Jan 2012, 11:08

Perhaps try a repeat of 0.25 (this should give you 4 images across the 360 degree view)

chon · 1 Feb 2012, 07:39

Using background images, VRay maps an image on the interior faces of a sphere representing the sky with your scene in the middle of that sphere.
So, on your image, you've got to represent both north AND south hemispheres with the horizon on the middle of that image like that :

Hope it will help you...

ali64risk · 3 Feb 2012, 16:33

@andybot said:

try a repeat of 0.25

this is a 0.25 repeat... as you can see it is still one picture in the background!

ali64risk · 3 Feb 2012, 16:41

@chon said:

So, on your image, you've got to represent both north AND south hemispheres with the horizon on the middle of that image

i understood what you said...
but why i should do that? I mean what happens if don't do that?
and how it helps me too have a tile texture in the background?

andybot · 3 Feb 2012, 20:50

@ali64risk said:

this is a 0.25 repeat... as you can see it is still one picture in the background!
I guess that's slightly less bad Maybe it's time to look for a different environment image - there's just not enough sky in that one...

ledisnomad · 3 Feb 2012, 21:10

@chon said:

in the UVWGenEnvironment, you've got a "repeat" option for horizontal and vertical settings.

When you set UVWGenEnvironment, is it also set to Spherical? I've always wished that there was a graphic representation of the environment map in the scene that I could manipulate. I always end up using an image in the reflect and refract and then add same image as a background in Photoshop.

chon · 4 Feb 2012, 05:29

ali64risk,

take a look on that VIDEO. It will help you for configuration.

Try to render your scene with my sky image. You will have a bad BG render because of low resolution but you will understand how it works.

To have good results, your HDR image must have a very high resolution.

On this exemple, the HDR image is 9000 pixels long and is a pure render, no photoshop postprod :

On the net, high HDR images sold are 12000 pixels long...

MarkNubs · 12 Jul 2017, 20:54

i just ended up here.
Fernando's trick seems doest work fully with sketchup 2016. so as new user i have to crack up my brain.

I simply used Text Mix in environment
Load the hdri in text A and set the Text Sky in Text B.Disable the Text C (Mix).
Then after series of trials. I unticked the Text B.

Seems working. Shadows apperared with affecting the hdri's intensity.
Hope thus helps.