Comments

Richard Jones wrote on 6/24/2018, 3:43 AM

Excellent. Wish I'd seen this years ago. Thank you.

Richard

Grazie wrote on 6/24/2018, 6:00 AM

As stated, you need to have a static shot of the BG and that that BG has the exact same Frame and lighting as the Motion shot. The issues start when the Motion then creates Shadows, which in turn create "holes" in one of the layers.

I've used this technique for a Local Government Service broadcast of a person descending a staircase - quite magical.

In any event it's a great 101 on employing the Power of the Compositing Modes, referencing their interplay and Multiple Parent/Child associations. Ron Scott is a great teacher and checkout any further Tutes by him.

Red Prince wrote on 6/24/2018, 8:48 AM

Very nice.

He who knows does not speak; he who speaks does not know.
                    — Lao Tze in Tao Te Ching

Can you imagine the silence if everyone only said what he knows?
                    — Karel Čapek (The guy who gave us the word “robot” in R.U.R.)

karma17 wrote on 6/25/2018, 6:48 PM

One mistake I kept making when trying this was I was trying to add the chain of effects to the track itself and not the Track Header. You know you are not on the header if the Composite button doesn't appear.

I would love to see more in-depth videos like this on Vegas.

karma17 wrote on 6/26/2018, 3:13 AM

I've been messing around with this all day and I've discovered a couple of things.

1. As mentioned in the video, when shooting your background and foreground videos, make sure the lighting is the same for the "backgrounds" in both the background and foreground shots. Since it is a difference mask, the same values minus each other will zero out and be black, which is what you want. If the lighting is different, the mask won't go to black and will require more adjustments, and may not work at all.

2. When filming the foreground element, if possible add additional lights on each of the foreground object that lights up the foreground object, but doesn't hit the background. If you can do this, it will result in a cleaner mask. You need lights on both sides to control shadows.

3. This technique requires massive rendering power. I guess because of all the calculations needed to make the mask.

4. In case anyone is interested, I've also discovered that if you use Threshold in the chain instead of Levels and Median, you get a much much cleaner and better mask.