Node problems, how to combine two render layers.

This may not be in the right section of the forums, but bear with me. This is my first major personal project, and I’ve gone to great lengths in planning to make sure that it doesn’t exceed my personal abilities.

However, I’m in need of some help.

Below are three images. One is just a close up of the spaceship, nothing fancy yet. The second is the really neat wormhole effect I came up with. The last is the ship’s render layer and the wormhole’s render layer combined. Now, this is just my drafting stage, I plan to draft out the video before going in and adding all the detail. But not knowing how to mix the two render layers will become a problem later.

So, if anyone has any idea what’s going on, please share, I’d really appreciate it. I also don’t want to release any files yet, as I was planning on giving back to the community with a very large file containing all the scenes once I finished. (Which will be a very long time) :slight_smile:

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Forgot the mixed image: silly me.

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Oh. And if someone knows how to add movie files to audacity, that would be nice to know too.

It’d help to see how your node set is…are you using an “alpha over”, “z-combine” or mix node? what do the alpha channels actually look like?

are you using premult?

I tried both z-combine, which is the effect shown in the second post, and alpha over as well. Both did the same thing, though I think alpha over didn’t show up at all.

As for the alpha channels, I’d have to take a look at those. Thats the little alpha buttons in the UV editor when you render, right?

And whats premult?

I recently had a similar issue with combining render layers. In my case I had a group of objects that I wanted to glow, so I put duplicates on a separate layer and gave them all shadeless materials, then added a blur in the node editor.

I couldn’t figure out a way to mix the layers using nodes, so I exported each layer as its own sequence of PNGs, then loaded the image sequences into the video sequencer.

To combine your renders using the sequencer, it looks like you would have to render the ship with the alpha channel intact, then use an Alpha Over to place it on top of the wormhole effect. To render with the alpha channel, go to the Format tab of the Scene buttons (F10), set the format type to PNG, and click the RGBA button underneath it.

I have attached some images to show you a basic example. zoom.jpg would be like your wormhole effect, over.png would be your ship, and final.png shows how to combine the two in the sequencer. (Your effect is much better than mine, of course, this is just for an example.)

I hope this helps!

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Hmmm. I didn’t think to combine the two PNG sequences in the video editor, have to give that a try. Thanks!

Hahahahahahahahahaha! It worked!

Though I used the alpha-over node, not the sequencer.