greenscreen with blender (with 2 small tutorials)

first let me say this has been a great weekend finding out that blender has the capablites of doing greenscreen with live film. adding cg to live action footage is a dream come ture for me and many other poeple on this forum.

huge thanks to
weirdhat- for showing it was possible
bob-holcomb- for working on his amazing version of blender with chroma-makea-somthing?
mstram- for uploading the special version of blender for us to test with until bob got his site back up!
huge thanks

*let me say this before anyone tries to start this tutorial

#1 i never ever wrote a tutorial before, so i dont know the proper words, i use words like ropes, blocks, because…i am simple
#2 this is a place to start, i just learned most of this a few hours ago so probably none of it is correct, BUT, the bottom line is this, i learn how to do it with just a screen shot and no prior knowlege of blender 2.42, so you have a huge advantage of having a step by step tutorial, with flashy picutres and such, so no complaints…mmmmmmkay
#3 finally if you are as excited as i am about learning this stuff, who really cares if its right or uses the correct words, as long as it works right!


what you will need
#1 you will need bob-holcomb’s special matte version of blender
Latest (VS7.1)Windows build (12 AUG 06-1830 EST)
Latest (32 bit) Linux build (13 AUG 06-1800 EST)

#2 for the first tutorial you will need two images, a image with a green background and a image you want to use in place of your green background. if you dont have one you can download the ones i used. (you can right click and save picture)
green image
background image

Nodes/Greenscreen with blender (2d image)
#1 open bob-holcombs special edition of blender (download at links above0, go to camera view, delete cube
#2 add a plane and size it to fit the camera window, add new material with new texture, select image in drop box of texture edit screen, load your image. (i like to go back and add shadless in material section)
#4 set your image size, turn off raytrace (if you want, it renders faster), click do composite, render a test (just to make sure you have an image).
#5 make a new material with a new texture, and in the texture edit section upload your second image (the background image) (you can use the same plane or create a different plane, just be sure the plane in the camera view renders with the image with the green background, before you move onto the node editor)
#6 go into node editor, click composite nodes, click use nodes, your render layers box will pop up (it should have your greenscreen image), and your composite box will pop up, remove the rope between the two).
#7 click add, input, image (this will be the background). load image your background image.
#8 click add, matte, chroma difference, set tolerance to about middle range, (whatever works best, but be sure to set it otherwise no green will be removed from your background).
#9 use rope thinger, to attach render layers box to chroma difference box, click key and select your color, green that matches your background, the color of the background you want to remove.
#10 click add, matte, color spill, click on green in the color spill box, the color of your screen background you are removing (attach rope from chroma difference top right to color spill block bottom left).
#11 click add, color, “alpha over” ,
#12 attach color spill image to the bottom image space on alpha over, this is your green screen image, attach your background image to the top image space on the alpha over block.
#13 attach your alpha over block top right image space to your composite block
#14 render your image, if all done correct you will have your green screen image with no green, and the rest of the image will be put ontop of your background image!

Nodes/Greenscreen with blender (animaiton with greenscreen)
#1 open bob-holcombs blender edition (download above), go into camera view, remove cube, and add plane to fit camera view.
#2 add new material, add new texture with material, select image in material settings, load avi movie
#3 click movie button, in material settings, set number of frames in movie in materail settings (i usually click the shadless option in the material settings).
#4 render settings, remove ray (this is up to you, it renders faster for me), set size, select avi jpeg, set quality of movie, select output, set frames a second, start end frames, be sure to hit “do composite button!”.
#5 add new material,( can use the same plane, just switch material back to green screen animation in the camera/render view before you go onto the nodes editor), add new texture to the new material, load new movie or 2d image (this will be the background image that shows up after the green is removed).
#6 go into node editor, click composite nodes, click use nodes, remove rope from “render layers” block to “composite” block.
#7 in node editor, click add, matte, chroma difference, attach rope from top right “render layers” block to bottom left “chroma difference” block.
#8 in chroma difference block click key and select color of the background you want to remove.
#9 click add, matte, color spill block, click on green or blue the color of the background you want to remove, attach “chroma difference” block rope to color spill box. (on chroma difference block, be sure to set tolerance, this sets how much green you remove, if you leave it on 0 then NO GREEN WILL BE REMOVED!).
#10 attach rope from composite to color spill box, and render a test, all the green background should be gone with just your image being displayed.
#11 remove the rope from your color spill box, from your compositor box.
#12 click add, input, image, select your second background animation or 2d image, to show in place of your greenscreen.
#13 if using animation, select “enable/disable” animation button, and add amount of frames in animation, and first and start frames
#14 click add, color, alpha over, attach your background image, to the alpha over, top space on bottom left side of alphaover box is for the background,
#15 attach with rope your color spill box, to the bottom image space in the alpha over box, the bottom image space is for your greenscreen animation/image.
#16 attach a rope from the alpha over box image (top right image space) to the image space on your composite box.
#17 go to render settings, select the number of frames to animate (should be the same as the number of frames in your green screen animation, i guess?) select a output location and render! (be sure your enabled the movie reading in your background movie clip, othewise it will not show up).
*this might be a bug i dont know, but when i save the blend file, and open it back up the background animation is gone? and i have add it back, but it seems to save fine when the background is just a 2d image and not an animation.

so there you have it, it is a bit rough around the edges, but i was able to figure all this out from just a screen shot, so i’m hopefull all of you will be able to get with two screen shots and some breif descriptions! good luck to all and to all a good night!

i will also post bob-holcomb’s tutorial as soon as he has it up!

helpful links
weirdhat’s green screen animation
deep thoughts green screen tutorial
weirdhats omg thread (helpful screenshots page #2)
bob holcombs rgb node thread (with blender downloads for chormakeingying…i dont freaking know)

Hey Wu you might want to check this thread out:

Well, Wu, one thing I can contribute is the location of bob_holcomb’s special version of blender!

Good luck on your quest for compositing knowlege!

EDIT: …aw…I’m too slow, you beat me to it!..well, that’s what I get for minimizing the window for a few minutes before responding…

BeBraw and Pseudo-G- big thanks for posting the links, i will try and download that version of blender tomorrow, and hopfully have some good starters to post, excellent!

the answers are coming…

thanks for the tutorial in advance. :smiley:

If you need help I might be doing the same thing as you but don’t really count on it. :D. I’ll try my best.

edit: where do you find the “loser’s footage”. the original one?


I’ll be happy to help with the tutorials when I get home. I’m visiting family and don’t have access to my machines right now. You can see a brief video of me demoing the green screen effect at blendernation in the videos from Siggraph. I’ll also see about getting my builds someplace more “stable” than my webserver. It seems to crap out on me from time to time.



PS. I’m usually on IRC as “Bobalicious” if you need to get ahold of me.

I can add this link into the mix:
It’s Bob presenting Blender compositing at Siggraph.

But I have to confess right here that I am devastated to find Wu in the support forums grovelling for assistance. My illusions, make that delusions, are shattered. My SuperWu animation was to end with Wu rescuing some women from the clutches of an evil-doer and flying off into the distance with them. I can see now I’ll have to re-think the ending. Maybe something with Wu drunk and slumped in an alley with a fluffy puppy dog taking a leak on his leg? I don’t know. I’m too depressed to think right now :frowning:

Why is nothing ever as it seems?

C0Rkn0T- i will do my best to get the tutorial correct and easy to understand, for now i’m just using a simple photo i created in photoshop wiht a green background to test, i dont have the link to the animation yet, baby steps…baby steps my friend, but the advanced stuff will follow.

bob-holcomb- is it really you…in person, haha, i’ve been following your thread carfully and have actally learned a lot, i’m going to download some of your stuff today and see what i can do, i got some tests to work just by using the seperate rgb colors…but your chorme key looks awsome, i will give it a try, by the way, i got some space on my site, and tons of bandwidth that almost never goes out, if you want i will host all your stuff there…let me know…great to have your help! -edit- yeah tired to download your blender version but the link is dead? about how big are each of the files? if they are around 8meg each it will be no problem to host them…you can email them here [email protected] and i will get them online for your…somewhere other then…what were you thinking?

andyD- if you want to be the man you have to beat the man, and now the man is weirdhat, so he is on the radar, once he is taken out i will accept your appology, so get your groveling skills ready…

mmmk mmmk.

I’ll be waching for updates :smiley:

and BTW: I got the video with the green screen.
^here’s the source from that Stephen Colbert’s Greenscreen Challenge, so you’ll have something to test on

It was worth coming to this thread just to read that :smiley:

Wu is definitely going to abuse chromakeying in his medieval short film lol

i got it to work flawlessly, so amazing to see the end result and to see how EASY it was to make, this is absolutly amazing to me!

i made both 2d images and animations with green screen following nothing but a screenshot bob-holcomb posted in his thread! on top of that i almost never touched blender 2.42 before!

i will write a short tutoral tonight and post it here tomorrow!

Wu is going to own greenscreening! whooooohoooooo! it will definatly be abused to death in the my next masterpeice film…if you didnt see “Space Slug Atack” your life has been a waste of time…

Great, all I need now is a green screen lol… Can’t wait until the tutorial is out.

My website should be fixed now. please let me know if you have any problems.



bob-holcomb- the site downloads fine with me, i hope the tutorial is cool with you, it was a bit rushed, but i was so excited that maybe i went overboard trying to learn blender 2.42 and your version of blender, and doing greenscreen stuff, and trying to write two tutorials, but i’m freaking out dude! this stuff is so great, and it works so well.

so i hope your cool with the tutorial and the basic description, i can add your tutorial as soon as you want, if you want, and let me know if you want to add to what i have written.

big thanks this stuff is FILTHY!

#1 you will need bob-holcomb’s special matte version of blender
Latest (VS7.1)Windows build (12 AUG 06-1830 EST)
Latest (32 bit) Linux build (13 AUG 06-1800 EST)

Latest Mac X.3.9 py2.3 build … ???

thank you so much. I’ll try it as soon as possible

andyD- dude grovelling…so not your style…anyway i asked bob-honeycomb specifically not to make that edition because you found it funny to laugh at the wu-man looking for help…yeah…this is the way it goes…yeah…you go against the force that is wu and this is the kind of thing that happens to you…you only have yourself to blame, by the way…24 hours to learn blender 2.42, learn nodes editor from a screen shot, get green screen to work with 2d and animations, and then write two tutorials isnt bad eh…never doubt wu-man again…for the force is strong…and super…

corknot- thanks, i really hope it works for you. it is very very rough tutorial, but it will give you some of the basics i hope on how to pull it off, then everyone can add to it and learn different was to greenscreen, just basically my notes on how i did it, just a starting place.

Well wuman (yeah, that’s “wu-” with a small “w” - like “woman”!), I had planned to write an in-depth tutorial about green screen during my lunchbreak - in between eating my sandwich and my apple. The only thing that stopped me pulling the rug out from under you was the ongoing world conspiracy against Mac users.

I should have just written the damned thing anyway then learned about it later. That’s how real tutorials are written anyway.

Other than that, it’s all looking pretty interesting again for the next release of Blender so I might just take a look at your “tutorial” for now. Oh, and thanks by the way.

bob-holcomb- I can’t access your site for some unknown reason. It just tells me that Internet Explorer cannot display your webpage. I tried it in Firefox as well, thinking it was a bug in IE (I have IE 7 RC1), but no luck.

EDIT: Never mind, it’s back up.

Anyways I can’t wait to try this out when I have a chance.