3

I have a Video of a face that I filmed with soft lighting and almost no shadows. The camera is a static portrait shot. Now I want a spot light to move slowly around the head. Is something like this possible in NUKE or After Effects?

illustration Note: Only the light should be done in post. The head should be real footage filmed by a static camera.

  • Do you have raw material? Can you add a styleframe to your question to understand what you are looking for? – p2or Jan 6 '15 at 18:20
  • It should look something like this: bit.ly/1s2awrJ But with a moving light and a filmed face. – Benedikt Jan 6 '15 at 19:04
3

I suggest build a real lighting rig and maybe stabilizing her neck.

If you decide to do it afterwards you have to:

  • Modeling the head and her hair (scan it if this is possible)
  • Tracking the shots with blender or pftrack
  • Replacing the head in your favourite package

There are some obstacles:

  • To get realistic shadows and highlights you probably need a better rendering engine for nuke
  • Detailed modeling is necessary to get the shadow right (espacially for the nose and the hair)
  • Modeling her hair can be a very difficult task
| improve this answer | |
  • Im not sure if I have to model the hair in that much detail. Can't I make a rough head and if I shoot in front of a green screen mask out the rest of the head – Benedikt Jan 9 '15 at 9:50
  • I think you have to, because shadows don't fall Linear and highlights are not only a bright spot on her hair, see: i.stack.imgur.com/TCKXZ.jpg Maybe you can fake the shadow with a mask, but to animate highlights and shadows by hand sounds tricky. – p2or Jan 9 '15 at 14:19
  • Would a point cloud or a scan with photographs work? vimeo.com/54931986 agisoft.com – Benedikt Jan 14 '15 at 16:43
  • @eundd Looks great, good idea. Unfortunately I don't have experience with the point cloud generator. With photo scans I have a bit, but for my purposes it never worked properly. If you decide to test it, let us know if it works. :) – p2or Jan 14 '15 at 19:18
2

Yes, it is possible in either, but the difficulty level is going to depend on how complete of an illusion you want.

The easiest effect is to simply setup a soft circle as an adjustment mask and apply an exposure increase to it. This will result in looking like there is extra light on the masked area of the shot. The problem is that it won't produce shadows or respect facial geometry, so it would look a bit more like shining a light on a painting.

You can compensate for this by roughly modeling the facial geometry and applying an actual light source in 3d in order to generate the brightening, but this would require modeling the face and matching the movements to those in the scene. Both Nuke and After Effects support calculating camera movements, but it is a complex thing to do, as is the modeling of the face and the animation of the face to fit the scene.

If you don't have weeks to dedicate to the task, it probably isn't worth bothering to try the more accurate version.

This is one of those things that is far, far more practical to handle in camera than it is in post.

| improve this answer | |
  • I know it would be better to do as much as possible in camera. What i wanna achieve is the light to move in slow motion around the head. So filming is kind of difficult. Modeling might be an option. Maybe a 3d point cloud. vimeo.com/89616610 – Benedikt Jan 6 '15 at 15:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.