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View Full Version : How to make an Alpha on Shake ?


Bezou21
04-23-2010, 03:52 AM
Ok here it goes, i have to do a 10 second trailer for my school project for Thursday.

Here is one of my biggest problem, i have to do the alpha of the 3D picture that i use in the little trailer. But i never remember how to do it. I have to do it on shake.

So now it look like that my 3D model is transparent. You can see my background trough my 3D stage. not really cool.

Anyone can help me and tell me how i can do that alpha. if possible by 2-3 way but not 10 hehe. Don't need to be perfect :P

I also got the same problem with my shirt. i was on a green screen, put a key light to remove the green screen but now my t-shirt is transparent again.

Damn i hate to use shake hehe.

Here the 2 link so you can see what i means :O

1: http://img339.imageshack.us/img339/2282/screenshot20100422at115.png

2: http://img339.imageshack.us/img339/8264/screenshot20100414at921.png

Here the problem is with my feet .. still same thing transparent but i was thinking about doing a rotoshape but i don't know if it gonna work out :S I also need to do the shadow of my body. I'm not moving my feet at all in that part.

3: http://img28.imageshack.us/img28/8788/screenshot20100423at123.png

beebop
04-23-2010, 11:23 PM
I think the reason your background is coming through you shirt is because your shirt is a color close to what you used as the green screen and on your arms is the spill from the green screen. Trying to do a better key may help some of that problem. As for the stage and your feet, I'm not exactly sure, but there's definitely something wrong going on with that. Don't know if any of this helps, hopefully you'll be able to figure it out. You could always just ask your teacher as well.

Bezou21
04-24-2010, 12:52 PM
i would like to ask my teacher but next time i see her, i'm gonna have to gave her my exam :S

Well someone told me to look to my multiply on my over that might be it, but now really.

So now i have to fin a another way to create an alpha :(

Bezou21
04-25-2010, 03:55 AM
ok so now everything is set .. only my stage .. i still try to do the alpha but nothing is working. Any advise pleaseeeeee. :(

oldblindbob
04-25-2010, 01:51 PM
alpha for stage... you can just draw a roto around your stage and that will create your alpha, or maybe add a luma key to it. simple way but should work.

transparent shirt... you could use a Primatte keyer and pull a really hard key to create a hard core matte, then use a dilate erode to shrink the matte a little, then pipe it into the 'holdout' of your Keylight.

transparent shoes... from what i can tell from your example pic is that you have your stage wired over your talent, if you swap them around it should be ok.

shadow... you can make a shadow by branching off a move3D from the talents matte, rotate and position to where you want then colour correct and place it back under the talent.

hope this helps :)

Bezou21
04-28-2010, 02:43 PM
Does anyone know how i can ungroup in shake ?
I just group, but i put one in a the wrong group. So i'm trying to split it but i dont know how :S

Never mind i find it :P

oldblindbob
04-28-2010, 02:53 PM
ungroup... highlight the group you just created, right click on it, scroll down to group and another side menu will open, then just choose 'ungroup'

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