How to use Blue-/Green screen in Blender?


(LaWMan) #1

Hi! I am currently doing some videowork in Blender, and I am having a hard time getting rid of the green screen in a proper way. When I set the Alpha slider to 0.0, the object itself becomes partially transparent.
I Know I must have some of the settings wrong, cause I have done it before only I do not remember quite how to do it.

Pls help me


(BgDM) #2

Lawman: are you pressing the ZTransp button in the marerial window? This makes the material transparent.

BgDM


(LaWMan) #3

Yes, I have pushed the ztransp button, otherwise the Alpha would not have affected it. But what I want is to insert a 2d-character into a 3d environment, so I want the green sorroundings of the character to be transparent, and the character to be solid shaded.

How to?


(S68) #4

Ok, got it

Take your 2D character.

Make a copy

Edit the copy:

Make the character all white
Make the green black

or viceversa.

Then use TWO textures:

One is the character, a COL map
One is the newly created black/white map, this must be an ALPHA not     COL texture.

Render.

Alpha is a three stat button. idf first render is not good pres it again and retry

cheers

Stefano


(LaWMan) #5

Grazie! Ce e una bella giornata, vero ? (about what I know in Italian, it’s probably not even right :smiley: )

I have been frustrating over this all day… Thank you S68, I can finally go to sleep now (not for good, but you know what I mean :slight_smile: …)


(S68) #6

Fine Italian :slight_smile:

“Ce e” is not correct thoug…

“Ci è” (stressed ‘e’, usually vritte “C’è”) is “There is”

A plain “è” would be “It is” and more appropriate for this sentence :slight_smile:

Let us see your anim when redy :slight_smile:

Stefano


(LaWMan) #7

Hehe I knew that something could not be right. Thanks for the correction :smiley:
I actually just remembered the Title of a chapter in my Italian book some years ago: A caccia di fungi (= mushroom picking or smth.)

Wow, actually now it’s all starting to come back.

Io sono LaWMan, sono une norvegese, Ho preso il treno per Milano alle nove… hehe Brings back memories.

By the way, the character is a real life person .avi texture, It is a movie project: A short film with blender sfx, a golden god that travels through wormholes in space and reaches earth and saves the chosen one from evil forces !!! :smiley:
The alphaMask part becomes a bit more tedious as it must be rendered through an editing software first. I thought that blender contained a kind of this-color-away button or smth, am I wrong?.

I just love the eyes of my friends when they watch what you can create in Blender in no time. :smiley:


(blenderanim) #8

I think the Chroma Key is what you want.

Here is a list of sequence plug-ins:
http://www-users.cs.umn.edu/~mein/blender/plugins/sequence.html

Check out the Chroma Key and the Alphamatte

Chroma Key sounds like what you want. It will allow you to key for a green or blue screen and even adjust the threshold if you don’t have a perfect background.


(LaWMan) #9

Thank you!
I must admit that I have been postponing the sequence editor tutorial for quite some time, now i finally see the need to learn it. :smiley: