Is there a way to convert an image with a bleck background to a bleck and white so that I can use it as a mask in Cycles? Here's the idea - From this: enter image description here

To this: enter image description here

I'm creating this Earth scene from "blenderguru.com" (link below) howeever, the clouds in Cycles are not visible enough and part of the clouds is fully transparent -

Internal - enter image description here

Cycles - enter image description here

Internal material -

enter image description here

Cycles material -

enter image description here

I don't know what it does in the Internal, but I expect the same result in Cycles. If anyone can explain to me why do clowds are less visible in Cycles?

Earth tutorial - http://www.blenderguru.com/tutorials/create-a-realistic-earth/

  • $\begingroup$ By the way, I used the same clouds texture for the Fac of the Mix Shader. $\endgroup$ – Vladimir Feb 26 '15 at 13:08
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    $\begingroup$ have you tried using index of object as a mask ? $\endgroup$ – Chebhou Feb 26 '15 at 13:10
  • $\begingroup$ not sure what you need, but you can add a color ramp to your cloud mask image (mix fac) to control cloud's transparency $\endgroup$ – Bithur Feb 26 '15 at 13:11
  • $\begingroup$ I did thought of that, but isn't there a way to just isolate/remove the clowds from the mask, 'cause the color ramp wouldn't do it perfect. I haven tried index for an image. I'll see how it works. $\endgroup$ – Vladimir Feb 26 '15 at 13:30
  • $\begingroup$ do you need your cloud's shapes or sphere's shape as mask? $\endgroup$ – Bithur Feb 26 '15 at 13:33

to create a mask from BW image you can use this nodes :

enter image description here

you can change the threshold for different results

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    $\begingroup$ color ramp (constant) can give easier/more visual control. $\endgroup$ – Bithur Feb 26 '15 at 13:43
  • $\begingroup$ You're right (I should spend more time on ramping). In the compositor when the ColorRamp is switched to "Constant" it separates it perfectly. Thanks for the answer. $\endgroup$ – Vladimir Feb 26 '15 at 13:52

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