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Dick Nelson
07-15-2003, 09:36 PM
I am having a couple of problems creating animations in Lightwave.

1. I want a transparent background (or backdrop--what's the difference, by the way), but don't see any such option. Seems like you either have to have a solid color, gradient or image. I want to be able to key the animation over another video source live in the switcher or in Toaster Edit. I guess I could use chromakey (using a green bg), but I would rather use an alpha channel.

2. After I render my animation and play it back in Aura or the switcher, it is not aligned properly on the screen. This occurs in both RTV and AVI formats. The alignment is fine in Lightwave.

John Fornasar
07-15-2003, 10:00 PM
but I would rather use an alpha channel.

In the Render Options panel, you can save an alpha. It's the bottom box. It doesn't seem to add any real time to a render.

The safest way to render an animation is to output separate frames. LW will number the files sequentially. If your computer dies in the middle of a render, you'll at least have your frames up to that point.

riki
07-16-2003, 12:14 AM
I haven't used Aura, but if you save out an images sequence of 32bit PNG files they will have a transparent BGD in Photoshop. Not sure if that carries across to other APPs.

Red_Oddity
07-16-2003, 02:52 AM
It does carry over to other apps, as Photoshop is a bit of a biatch when it comes to desciding when to use a layer with transparancies or when to use a real Alpha channel...(I really really hate PS7 for this, as there is absolutly no friggin clue as to when the layering happens or when it uses an alpha (same goes for saving files these days in PS7)...time for another company to de-throne Adobe and do it right for once)

As for Aura, any 32bit (or 64bit) will do, as it will automatically save the Alpha in the file (no need for the seperate alpha files...unless you use it for the oldfashioned Beta taped alpha trick studios seem to use so much...)

Dick Nelson
07-16-2003, 07:47 AM
I really appreciate the suggestions but now I am REALLY confused. I saved the animation as alpha files, which gives me a whole bunch of sequencially-numbered targa files that are merely white on black. In addition I get an AVI (or RTV--depending on what I've chosen) file with the full-color animation and solid background.

I know how to import a sequence of images into Aura, which I could do with the targa files, but what good is that going to do me, since they are just black and white?

There's also an option for saving RGB files (apparently in JPG format). What are those, and can I make use of them?

riki
07-16-2003, 08:06 AM
If your trying somthing new, that your not sure about it's always a good idea to do a test with a couple of frames before you commit to a full render.

Just follow Red's advice and output 32 bit sequence.

B/W that's the nature of the beast when it comes to Alpha channels. Black is for transparent, and white is for opaque, I always get this mixed up, it could be the other way around, but anyway you can do a quick test and in any case your APP should know how to read the information.

danilo
07-16-2003, 08:27 AM
...time for another company to de-throne Adobe and do it right for once)


Agree 120 %.
danilo

Dick Nelson
07-16-2003, 10:50 AM
It sounds to me like I can't do what I'm trying to do. It looks like I can get an animation with alpha channel, but only in b&w, OR I can get one in color, but not with a transparent background. Unfortunately neither option is acceptable, so I may have to do the chromakey thing.

Dick Nelson
07-16-2003, 02:14 PM
PNG rocks!

Saving the animation as a series of png files, then importing these as a sequence into Aura worked like a charm.

It's then possible to export the sequence as an RTV file, which will key in Toaster Edit (I haven't yet tried the switcher, but I assume it will work there, too).

Aegis
07-16-2003, 05:21 PM
Why not cut out the middle-man (Aura) and render an animation straight to RTV?

John Fornasar
07-16-2003, 05:23 PM
Don't get confused... you're NOT saving an .avi file

Save sequential frames of your "color" shots with the solid background, and at the same time, save the alpha sequential files... bring them into your compositing program, and place them in front of your source video.

Here's how the render options will look...

edit...

whoops, I would probably have selected targa's for both the frames and the alphas, I just clicked that one up fast...
and in the future I'll probably try just working with an embedded alpha format, right now I'm just stuck in my old habits...

Dick Nelson
07-16-2003, 09:03 PM
From Aegis:

>>Why not cut out the middle-man (Aura) and render an animation straight to RTV?

That's exactly what I would LIKE to do, but, as I pointed out above...

1. I can't get a transparent background when I render as an RTV or AVI file.

2. The rendered output is not aligned correctly.

With PNG files everything worked perfectly. Just had to go through the one extra step in Aura, but that was no big deal.

From John Fornasar:

>>Save sequential frames of your "color" shots with the solid background, and at the same time, save the alpha sequential files... bring them into your compositing program, and place them in front of your source video.

There's no need to save the alpha files. Just saving the "color" frames as PNGs does the trick fine.

marvin
07-17-2003, 11:03 AM
It was actually that you saved them as PNG 32 that did the trick. If you were to have saved them as PNG 24, then they would NOT have had the alpha channel embedded in them.

color:
R = 8 bytes
G = 8 bytes
B = 8 bytes

alpha:
Alpha channel = 8 bytes

marvin

marvin
07-17-2003, 11:05 AM
Sorry. Didn't get to finish...

R + G + B = RGB
8 + 8 + 8 = 24

or

R + G + B + Alpha = RGBA
8 + 8 + 8 + 8 = 32

marvin