View Full Version : a simple set up...

06-07-2010, 05:27 PM
learning nuke....

1. how do i do a very simple quick comp one backplate and one 3d layer with alpha, i try using merge and the layer looks though its a screen layer even though its not set to screen?
In fusion i would bring in two images merge them and voila, it automatically read the alpha. there a way to view layers and images without attaching them to the viewer? pressing one does it but it also attaches them to the viewer. In fusion all i would do was drag the image to the screen and it would display the image.

an idiots guide please...

06-07-2010, 06:04 PM
1) If it's your foreground layer that looks screened, you need to premult your FG before merging it, or use the "matte" operation in the merge node (which handles this for you).

2) No. Viewers are discreet ops that can perform color lookups and other viewer-specific processes for display purposes, and thus you need to hook them up to the op tree for them to receive/process any data.

06-07-2010, 08:11 PM
thanks for the tips however....

1. My top layer is a targa image with an alpha embedded, I'm trying premultiply and not getting it working it just makes the background black ie doesn't show the alpha. in fact im trying every type of layer possible and not getting the result im after im trying it ni fusion and after effects and no problem...i know it must be me! but what!

2. So there's no other way to view my images on the display other than attaching them all to a viewer?


06-07-2010, 09:15 PM
Do you have the pipes hooked up backwards? Your background should be in the B pipe...

Can you copy and paste your nodes into a reply and wrap them in CODE tags? From your description, it's likely that either your image has no alpha channel, or your merge node has the alpha for the FG source unchecked, but it's hard to diagnose with nothing to look at.

As for viewers, no there is no other way. That's just how viewers work in Nuke. But it's just like Fusion in that you press 1 and there's your image from whatever node you have selected.

06-07-2010, 09:19 PM
Can you post a frame of the FG to or something?

06-07-2010, 10:14 PM
i got it....

yeah the A B thing!! thanks

so the way i did that was to click on my foreground layer and add my merge that way other wise I couldnt seem to get it to go to A it always wanted to go to B...

so last thing... how do you specify which one you want to connect to ? is there a way to swap inputs?


06-08-2010, 12:49 AM
Shift + X swaps.

Edit -> Preferences-> Preferences Tab -- Node Defaults: "New Merge Nodes connect A input"

Uncheck that if you want it to go to the BG by default.

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06-08-2010, 12:49 AM
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