View Full Version : alpha help

01-25-2004, 05:36 PM
i know i saw this discussed somewhere else in the forums but after searching for a half hour i decided to ask:

im having this logo go twirling around some guys head but how can i get it to go behind the head? the guy is on a backdrop

cant i use a null or something?

01-26-2004, 05:28 PM
is not a simple question, if you want to do all in lw, you need to build an objects with the shape of boy's head, use it with front projection to delete logo when it go behind head.

if you want to work with compositing (better way) you must build a mask (with spline in after effects for example) and delete from logo layer the part which is relative of head zone.

01-28-2004, 01:02 PM
What post production tools do you have????

you could cut the head out of the pic / movie you are using as a backdrop and layer it in front when you want the logo behind.

Dead easy to do in photoshop or whatever with a still backdrop...gets a bit more lengthy when your using a movie.


PS, Logo text made in lightwave

01-28-2004, 01:10 PM
thanks for the replies :)

it is a movie, so yea, it'll be hard, 24 frames for every second

i could do all that in photoshop, counting on i will have enough time, but is it possible to import a video clip into photoshop? i noticed under the filters tab "Video"/"De-Interlace"... so...

01-28-2004, 02:22 PM
Its "image ready" you need to be playing with.

To be honest, i dont think your gonna find a quick solution to this!

Compositing (in my eyes) is one of the hardest and time consuming things to do.

Unless some of the pro's out there have some great tips?????

Rob T

01-28-2004, 05:15 PM
i wonder if there's any motion tracking program that could seperate it into a motion layer and a non-motion layer...

this is gonna be a #@$&!

01-29-2004, 10:51 AM
Do you wanna chuck the files on here...

I wouldnt mind having a play, to see what i could do?

Rob T

01-29-2004, 11:23 AM
after effects. absolute staple in any video/compositing studio.

01-30-2004, 08:57 PM
question: is it possible to render the alpha as a movie file in lightwave or do you have to render each image?


01-31-2004, 04:32 AM
If you render it out as a quicktime *.MOV it will contain the alpha information you want.

Then you can manipulate it in whatever package you have.

But you cant render just the alph on its own. (as far as im aware)

01-31-2004, 07:17 AM
in redering options paneel you find save alpha checkbox,

upgrading to LW8 now brings you DFX with one of the most powerful trackers included, much better than eg in AE