Adding Screen Mode & 3D Ability to Same Event

Wepogo wrote on 8/25/2020, 11:42 AM

Hello,

I am trying to add a special FX to a video. This VFX is a "Harry Potter" wand effect (like a burst of electricity sent from a magic wand) and it is with a black background. In order to make it work, I need to change the compositing mode of the track to "Screen". So far, so good.

However, I would like then to position this event in 3D, and for that I need to select the compositing mode called "3D Source Alpha" in order to use "Track Motion" in 3D with the ability to rotate the X, Y and Z axis.

The question is: how do I do that at the same time, for the same event, since you can only select one compositing mode?

Is there a "screen" compositing mode plug-in available? Or a 3D position plug-in available? I am aware of the Mask Generator, but it removes all color from the VFX.

Thank you for your help.

BR,
Wepogo

Comments

joelsonforte.br wrote on 8/25/2020, 12:34 PM

You can use the Chroma Key effect to remove the black background and then apply the "Screen" compositing mode to the track.

Marco. wrote on 8/25/2020, 1:47 PM

Another option which leaves the choice of using the Screen mode:

- Add an empty track above your existing two.
- Make the second track to a composting child of the first track.
- On the first track set the Parent Compositing Mode to "Screen".
- Open the Track Motion window of your second track then set Track Motion to "3D Source Alpha".

 

Wepogo wrote on 8/26/2020, 1:54 AM

Hi @joelsonforte.br,

Thank you for your suggestion! However, using the Chroma Key in this context creates some artifacts around the VFX, and it doesn't look good. The Screen compositing mode works much better in this example, it only leaves the VFX visible with no artifacts. around it

For reference, here is the pack that I am using for the VFX:

fr0sty wrote on 8/26/2020, 1:57 AM

Marco's recommendation is the best way to go about it.

Wepogo wrote on 8/26/2020, 2:01 AM

Hi @Marco.,

Thank you as well for your help! I tried your solution but unfortunately the black background is not removed on the VFX. Here is what I did:

  • 1st track: Empty track set to Parent and Screen compositing mode
  • 2nd track: VFX set to Child of 1st track and 3D Source Alpha compositing mode
  • 3rd track: video track with footage in normal mode (no Parent/Child and Source Alpha compositing mode)

It seems that a child does not inherit the compositing mode of the parent. Did I do something wrong?

Wepogo wrote on 8/26/2020, 2:08 AM

@Marco.,

Nevermind my previous post, it now works!

What I did wrong: when setting a track as parent, there is a new "Parent Compositing Mode" button that appears on the left, and this is the one to change to "Screen". I only changed the compositing mode using the usual button on the right side of the track. This one should be left to Source Alpha.

It now works as expected and I learned something 😄. Thank you again for your help! I wish you all an excellent day.

Cheers,
Wepogo