Dear Riakiotakis,<div><br></div><div>Alpha without transparency is not incorrect, it is just one more option for composing that I would like to have. </div><div><br></div><div>Consider this scenario: In a outdoor render, I have ground, buildings and trees (leaves have oppacity masks), and a sky. In the composition I want to compose the render with an AO pass. Without an alpha to mask AO, the sky would get black. I canot use masks based on objectID, due to leaves transparency...</div>
<div><br></div><div>In this case, using alpha mask is just fastest and the fring pixels are no matter at all.</div><div><div><br clear="all"><div><div><br></div><div><div>Adriano A. Oliveira<br></div><div><div><div></div>
</div></div></div></div><br>
<br><br><div class="gmail_quote">2012/12/8 Antony Riakiotakis <span dir="ltr"><<a href="mailto:kalast@gmail.com" target="_blank">kalast@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="im">><br>
> I understand the risk, but this option is usual in many renders, like Vray.<br>
> The alpha is just an information that can be used in compositions. Some<br>
> times is good to have alpha mask just to saturate a non-trasparent<br>
> background, without the need of complex render layers, for example.<br>
><br>
> I think it is more intuitive that the alpha slot in render layer always give<br>
> alpha mask, no matter the trasnparent status.<br>
><br>
<br>
</div>It's not a risk, it's incorrect behaviour. In your use case, any alpha<br>
mask will take non-background colours in the result. The colours at<br>
the edges of the background will be incorrect.<br>
<br>
Intuitive != correct.<br>
Also, "many others do something" != "it is right"<br>
<div class="im"><br>
><br>
> I believe in freedom :D<br>
><br>
<br>
</div>As opposed to slavery in correctness? Freedom to be lazy is acceptable<br>
I guess. I also get bored when I need to setup render layers. But such<br>
grand proclamations are a bit out of context I think.<br>
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