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Gradient Alpha on transparent object
Hi,
I’ve got transparent object which has alpha gradient applied to smoothly restrict reflection and refraction area. The problem is that the gradient doesn’t work at all in this case. It creates sharp cut between where the object is seen an where is not. I think that it isn’t possible in standard renderer, but maybe some more advanced user has some solution and could save my life ????See attached preview file and project to know what exactly it’s about.
I’m using standard renderer in C4D R17
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8 Replies
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I checked the project and I coundn’t simply solve it. The problem arises I think because once you add an alpha, the transparency can only be evaluated where you have at least a partially seen object. You see the clear bound where transparency was computed and where it wasn’t.
The only solution I have is to compose the ripple in post with some render passes. Essentially separate the BG and render all the rest with a full alpha then add just the alpha to smooth the transition in post.
Cassius Marques
http://www.zapfilmes.com -
Cassius, thanks for the answer,
I was hoping to avoid doing such a things in the post regarding to double time render etc. By the way, is that only standard renderer issure? Is it achievable in other render engines such as Arnold or Octane? -
Can’t say about arnold, but I do get a clean alpha with octane just by converting your material and changing it to specular.
I didn’t convert anything else to the render pipeline. So that screen is just 1 material plus the auto converted default one you had.
I’m guessing you’ll only have trouble if you must combine transparency AND alpha. Most renderers don’t even have both. They are one and the same in any PBR plataform (should be IMO).
Cassius Marques
http://www.zapfilmes.com -
Yeah, that looks nice. Shame I can’t do this with standard renderer.
Thanks Cassius! -
I get a similar result in the Corona renderer. – FWIW I found a huge difference in Physical in how the gradient fades off if you turn Linear off…
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Hey Brian. I’m not sure if I understand what exactly do you mean by turn “Linear off”. Where is that option?
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it’s in the Project Settings – there is a check box near the bottom Linear Workflow – read about it in the help – side effects would be all your textures will change somewhat and I don’t even know if it will make it possible to do what you want but there is a different nicer fade to the gradient alphas when I stop Linear Workflow
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Yes, got it. Unfortunately it doesn’t solve the problem. Finally I’ll have to compose two separate renders.
Anyways, thanks for help!
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