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Solid background
Posted: Thu Oct 25, 2012 12:40 am
by arch3d
Hi,
I would like to create solid background (e.g.RGB=128,128,128) It should't affect on rest of the scene.
Saving flat image as HDR and connecting as background is only way to do it?
Any ideas?
Ty for help
Re: Solid background
Posted: Thu Oct 25, 2012 4:53 am
by rusteberg
you have obviously found a solution.
so what is your question?
Re: Solid background
Posted: Thu Oct 25, 2012 9:13 am
by arch3d
I was looking for different (faster) solution

Re: Solid background
Posted: Thu Oct 25, 2012 11:15 am
by JDHill
You can use IBL, use sky dome in the background channel, and use a pure white HDRI (
here's one) in the other channels. Depending what you are trying to do, you may also want to use sky dome in the reflection and refraction channels. Benefits of doing it this way (as opposed to putting a color HDRI in the background channel) are that you can change the background color at any time, and also use the sky dome's gradient capability, if you want to. If you absolutely need a specific color, though, the only way will be to render with alpha and comp the background in later, since things actually in the scene will be affected by the camera exposure.
Re: Solid background
Posted: Thu Oct 25, 2012 12:46 pm
by Fernando Tella
Render with Alpha channel and compose in post. I think it's the fastest and more flexible solution by far. At least for stills.
Re: Solid background
Posted: Thu Oct 25, 2012 2:27 pm
by arch3d
Hi,
Thank you for respond.
I am trying to do absolutely neutral environment

So i am testing ground material (with gradient as opacity) - it will "catch" shadows of objects and get get rid of horizont line. If my ground will be partial transparent i have to use same one color background.
JDHill - I want to use emiters to get nice lighting, so i dont need to use any extra illumination
Fernando I don't want to use Alpha. It demands extra post production time and i notice that if i use passes render calculates longer...
Cheers
Re: Solid background
Posted: Thu Oct 25, 2012 3:22 pm
by hatts
I think I understand now, but I can agree with Fernando in that what you're trying to do would take far longer than post production, and is less flexible.
Adding alpha and/or shadow channels to your render adds only negligible render time if any, whereas tweaking your strange disappearing floor will only cause pain, and will essentially flatten your image.
Post-production is a fact of life...embrace it...
The documented Next Limit solution really does seem to be the best way:
http://support.nextlimit.com/display/ma ... ow+channel
Specifically the part about "Knocked out shadow pass vs Full shadow pass"
Can you link to an example image of what you're trying to achieve? Just a bit puzzled because you seem experienced enough to know why we're recommending the alpha clip solution.
Re: Solid background
Posted: Thu Oct 25, 2012 7:02 pm
by rusteberg
do the alpha....
Re: Solid background
Posted: Thu Oct 25, 2012 8:33 pm
by arch3d
arch3d wrote:rusteberg wrote:do the alpha....
Perfect example

Thank you.
I will use this image to calibrate monitor
I always render with passes. It's best solution.I know it.
But this time I am looking to archive one colour "infinite surface" effect without alpha.
Same effect as rusteberg shows...but without alpha.
No progress yet:(
Re: Solid background
Posted: Thu Oct 25, 2012 9:51 pm
by rusteberg
you mean like this?
original test with grey:

Re: Solid background
Posted: Thu Oct 25, 2012 10:04 pm
by arch3d
rusteberg wrote:you mean like this?
yess.... You did it
I just made some tests and almost did it using classical light studio technique...
..but i had to reduce Burn to 0

Re: Solid background
Posted: Fri Oct 26, 2012 3:41 am
by rusteberg
arch3d wrote:So i am testing ground material (with gradient as opacity) - it will "catch" shadows of objects and get get rid of horizont line. If my ground will be partial transparent i have to use same one color background.
it sounded like you were heading in the right direction. keep testing this. if you use the same color for the masked ground plane as the solid color background hdri, then all it comes down to is calibrating the light in your scene in order to match the two colors harmoniously. all it takes is some fine tuning until you find a delicate balance between the three (ground with gradient, solid color hdr background, and illumination..... this one happens to be lit with three emitters)
keep going....

Re: Solid background
Posted: Thu Nov 01, 2012 9:17 pm
by Q2
Hi Guys, can you show us your scene setup? Where did you place your emitters and how was the scene set up?
Cheers
Q!
Re: Solid background
Posted: Fri Nov 02, 2012 6:33 am
by rusteberg
have fun!

Re: Solid background
Posted: Tue Nov 06, 2012 11:25 am
by Q2
Thanks Rusteberg! As always a very good explanation!
Q!