Green Screen red dots at DVinfo.net

Bev Standish · March 6th, 2005, 09:15 PM

Can someone explain to me what those little red dots mean on the green or blue screen? I am assuming they are reference points for tracking but I just can't seem to comprehend how it all works together.

Thanks a million

Bev Standish
Wolfsong Studios

Rob Lohman · March 7th, 2005, 04:19 AM

They are indeed for tracking, sometimes with a different color
(like white) as well. Mainly to see how camera moves where done
and allow to track those shots for compositing reasons.

What else do you want to know?

Bev Standish · March 10th, 2005, 04:34 PM

Thanks so much for replying to my post. I am trying to visualize how these reference dots work. My question is, what is the workflow? I have a CG background and am wanting to composite live actors against a green screen. So I understand I key out the green out but leave the red dots? What do I do with the dots?

Thanks again

Bev

Richard Alvarez · March 10th, 2005, 05:30 PM

The reference dots are for camera tracking movement. In other words, they allow you to follow the camera movement, without any depth of field reference that you normally get through visual references.

The actors are standing in a green room. The camera pushes in, booms up and swings left. Hard to know what's happening to the background images... when there's nothing but green background.

This information is then compared with the matte background, so that the camera movement of the background matches the camera movement of the foreground. (Such 'camera movement' might actually be a simulated cg background of course)

Follow?

Jonathon Wilson · April 2nd, 2005, 11:16 PM

Right - to just say the same thing another way:

1) Shoot the greenscreen with the tracking dots.
2) Import this into your CG application, (play it as a background, keying out the green) and then put fixed objects in the CG scene at the same location as the tracking dots.
3) Now move your CG camera such that your synthetic (CG) tracking dots 'move' the same way as the tracking dots in the original footage.

This means you have matched a CG camera move to the move the real camera did.

This will allow your synthetic background to match up with the real camera move on the live action.

March 6th, 2005, 09:15 PM	#1
Bev Standish New Boot Join Date: Feb 2005 Location: Tigard, Oregon Posts: 6	Green Screen red dots Can someone explain to me what those little red dots mean on the green or blue screen? I am assuming they are reference points for tracking but I just can't seem to comprehend how it all works together. Thanks a million Bev Standish Wolfsong Studios __________________ Bev Standish Wolfsong Studios

March 7th, 2005, 04:19 AM	#2
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	They are indeed for tracking, sometimes with a different color (like white) as well. Mainly to see how camera moves where done and allow to track those shots for compositing reasons. What else do you want to know? __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

March 10th, 2005, 04:34 PM	#3
Bev Standish New Boot Join Date: Feb 2005 Location: Tigard, Oregon Posts: 6	Red Dots Thanks so much for replying to my post. I am trying to visualize how these reference dots work. My question is, what is the workflow? I have a CG background and am wanting to composite live actors against a green screen. So I understand I key out the green out but leave the red dots? What do I do with the dots? Thanks again Bev __________________ Bev Standish Wolfsong Studios

April 2nd, 2005, 11:16 PM	#5
Jonathon Wilson Regular Crew Join Date: Feb 2004 Location: Austin, TX Posts: 182	Right - to just say the same thing another way: 1) Shoot the greenscreen with the tracking dots. 2) Import this into your CG application, (play it as a background, keying out the green) and then put fixed objects in the CG scene at the same location as the tracking dots. 3) Now move your CG camera such that your synthetic (CG) tracking dots 'move' the same way as the tracking dots in the original footage. This means you have matched a CG camera move to the move the real camera did. This will allow your synthetic background to match up with the real camera move on the live action. __________________ http://www.aqua-web.com

March 10th, 2005, 05:30 PM	#4
Richard Alvarez Inner Circle Join Date: Sep 2002 Location: San Mateo, CA Posts: 3,840	The reference dots are for camera tracking movement. In other words, they allow you to follow the camera movement, without any depth of field reference that you normally get through visual references. The actors are standing in a green room. The camera pushes in, booms up and swings left. Hard to know what's happening to the background images... when there's nothing but green background. This information is then compared with the matte background, so that the camera movement of the background matches the camera movement of the foreground. (Such 'camera movement' might actually be a simulated cg background of course) Follow?