Changing background on photoshop
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Hi everybody, i'm trying to learn a bit of photoshop, i want to change the background of a vray render i've done.
i never used photoshop before. Does anybody knows a tutorial showing how to do this?
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Hi,
Toxicvoxel recently post this link and i've found tons of great tutorials, but you need a basic understanding of photoshop to follow them.
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thanks for the link, i'll take a look. i don't know anything about photoshop..
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Changing the background is a bit ambiguous. What kind of background is it? Do you have an image you could post to show what you are talking about? Any chance that V-Ray exports the background as its own layer? Then it would be simple to switch...
Chris
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i think it's simple... when i do a render, vray creates an alpha image and an normal one, i'll post them, so that you know what i talking about.
what i want to learn is to keep only the render part(the white on the alpha), remove all the rest(the black on the alpha)and place a new image on the background.Alpha:
Picture:
thanks
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Hi,
I can't see the Alpha image?
Maybe it's just me?
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well...i can see it...
but if you can't see, in the alpha the blue is black and everything else is white. -
You need to open the diffuse image...the coloured one...then down at the bottom right, click on the Channels tab. It's on the same menu as layers. Click on the little icon at the bottom of the tab that says Create new channel. You'll get a new channel...already called alpha...that is coloured entirely black.
You now need to open the V-Ray alpha map. Select > All, then Edit > Copy...then paste that copy into the alpha channel on the diffuse file.
I should add that this needs to be done before you crop or resize either image, otherwise (obviously) they ain't gonna fit.There's another little icon on the left of the channel tab that will convert that channel into a selection. When you have got the selection; make sure it's the right way round (ie that the sky is selected, not the house...if it's not, go to Select > Invert).
When the selection is correct, select the RGB channel at the top of the list and go back to the layers tab.Choose background eraser (hold down the ordinary eraser till you're offered a choice) then click the eraser in the sky and press delete. All the sky will disappear...you'll see a checkerboard background...and the remaining picture will turn into a layer.
You can now bring in another sky or background and place it behind this layer to complete your image.Click on the Layers menu > Flatten image, when you are happy with the composite.
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Thank you very much Alan, i was able to do it thanks to your explanation.
I needed something like that, step by step, because i opened photoshop today for the first time and i know nothing at all about it!Once again thank you.
This forum is the best!
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Hi Alan,
Thank you for your short tutorial. Now I finally understood how to use alpha masks in PSP. That brings me a little further into the question I had asked in this topic.
http://forums.sketchucation.com/viewtopic.php?f=40&t=23243
Thankyou
Karlheinz
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