Help with transparency using 3d scene

[Anonymous]

Hi Fellas!

I ‘m new on composition, but i’m plenty of energy 🙂
I have a question for Nuke users. Try to learn to composite 3d scenes based in this tutorial

http://www.cmivfx.com/i/mov/nuke_002.mov

I’m stuck on the step when the 3d card containing the rain becomes transparent. I apply luminance key to a image, and it works perfectly in a simple 2d composition, but when I apply it to a 3d card node, i can’t eliminate the black background of the keyed image…

I really appreciate any help.

Best regards!

[Anonymous]

Andrex wrote:

Hi Fellas!
simple 2d composition, but when I apply it to a 3d card node, i can’t eliminate the black background of the keyed image…

premult

[Anonymous]

Here is a screenshot of the composition

http://img61.exs.cx/my.php?loc=img61&image=nukescreen2aw.jpg

Before 3d card node there is a Premult node, but nothing happens. Note that superior viewer is the result, and in the second viewer (3D) you can see how composition is made.

[Anonymous]

Anyone?

[Shervin Shoghian]

Andrex wrote:

Anyone?

PreMultiply the image dude.

Swerve.

[Anonymous]

You may want to check your options in your scanline renderer.

[Anonymous]

Check your BG layer for Alpha, if there is no ALPHA generate white one.

[Anonymous]

OK Guys, Definitively I’m doing something wrong. Considering the large quantity of parameters to consider, if I decide to solve this by myself, possibly in a couple of years I will do 😛

If you guys can teach me step by step the way to create a 3D card with transparency (like a croma key or a mask) over another 3d card in a 3D scene, I will be eternally grateful.

Thanxs for your patience with this rookie.

[Anonymous]

Darkhorse wrote:

You may want to check your options in your scanline renderer.

Hey there. Darkhorse is right, Double-click your ScanLineRender node, the option box will appear. Make sure the “Alpha Blending” box is checked. This makes sure your transparencies (like your keyed image) will be visible in the 2D viewer.
Don’t confuse this with the “alpha blending” checkbox in the 3D viewer settings.
This seems to be checked on by default. Uncheck it and suddenly your 3D viewer has the same problem! I would say, give it a try!

Hope this helps. See ya!

[Anonymous]

At last!

Thanx a lot all of you Guys!!!

😀

[Author]

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