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Comping a distant mountain and guy close walking towards it....sigh

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Sigurdur TraustasonComping a distant mountain and guy close walking towards it....sigh
by on Apr 29, 2014 at 6:56:36 pm

Hi everyone, I'm new here and I decided to ask a question here, since I've often been taken here when I google my problems.

Anyways, I'm working on a clip where I need to comp a distant mountain with another close clip of a kid walking towards it before fading out. Thing is, both clips have some motion it it (actually a lot) and there is no green screen in the clip with the kid. I have frozen the mountain clip and masked the ground out from that so that's not really a problem. The mountain is on a layer below the kid layer.

Okay, so the main problem is...tracking the kid shot seems to be next impossible, since the kid walks from the right side of the frame to the left side, then back while walking away from the camera and it's all really messy. The camera also shifts from left to right, back again and the only reliable tracking points I have is the horizon line separating the sky and ground.
Since I'd probably need to mask the sky out to use the mountain and the sky from the mountain layer, it's going to be hell rotoscoping the kid as he ventures left and right then left again and since he cuts through the horizon I'll need to rotoscope him everywhere above the horizon. I hope this makes any sense. I'm having a hard time first of all blending the end of the ground with the mountain to make it look soft and smooth, it just gets really jagged and clearly two separate clips. Dunno if it's the lighting or what. Then because the kid clip is going all over the place both on X and Y, I think it's going to be next to impossible to rotoscope the ground on every frame without problems.

One thing I tried just now was to change the masks, instead of masking out the sky from the kid layer, I masked the mountain out, removing the sky and the ground from the mountain layer and leaving the sky and ground on the kid layer (o my god it's hell trying to explain this). Anyways, this way I can at least use the mask on the mountain layer to rotoscope the kid but there's still the problem of bad blending on the horizon and the motion on the kid layer since the ground is all over the place.....or maybe that's partially okay since the mountain is so far away. Jesus, I hope someone understands, just figured out how to add a picture, I hope those can explain something







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Darby EdelenRe: Comping a distant mountain and guy close walking towards it....sigh
by on Apr 30, 2014 at 4:14:14 am

The picture you posted of the foreground footage looks like a perfect candidate for the Keying > Extract effect. The sky is very bright and the foreground is relatively dark, it should be fairly straightforward to create an alpha from that (Extract would be the easiest way). Then you'd just need to stabilize the shot and do some edge cleanup.

If you do a rough mask to remove the character's motion from the clip in a precomp then the Distort > Warp Stabilizer may be enough to stabilize the clip. If you get good stabilization you can then turn the mask in the precomp off to bring your character back.

For edge cleanup you have a few options again but one of the Refine Matte effects would be a good place to start.

Darby Edelen


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Sigurdur TraustasonRe: Comping a distant mountain and guy close walking towards it....sigh
by on Apr 30, 2014 at 5:56:29 pm

thanks for the reply. Those are some things I've never been introduced to. I'll see if I can look at some tutorials.

I've done some tests to see what this would look like if I manage to mask the kid out, just rotoscoping the whole clip. It would be tedious but it could work partially, if only the clip would be stabilized first. Rotoscoping the kid is no longer the heavy issue.

Here's one frame where I've pulled off a separate mask on the mountain layer just to mask out the kid frame by frame.



Clearly I am losing some detail like the strands of hair on his head but I'm not gonna pursue that issue. I also tried placing an adjustment layer on top of everything, I've got thin masks running across the horizon on both sides of the kid, putting some blur effects and stuff like that attempting to blend it together and make it less jagged. I'll need to rotoscope that a little so it doesn't go across the kid but I'm fine with that.

I'm gonna take a look at what you've recommended. Thanks again for the reply.


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Michael SzalapskiRe: Comping a distant mountain and guy close walking towards it....sigh
by on Apr 30, 2014 at 6:22:33 pm

The Roto Brush with the Refine Matte effect might do a quick job of this for you (and preserve those hair strands).
If you've never used it before, go through some of these resources [link] first because it's not as intuitive as it looks.

In case the Roto Brush or the previously mentioned Extract tool don't do the trick, there are some very useful tips here [link] for more traditional rotoscoping.

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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Sigurdur TraustasonRe: Comping a distant mountain and guy close walking towards it....sigh
by on Apr 30, 2014 at 9:20:44 pm

yeah thanks for the reply.
I tried the Extract tool and it seems to do amazing things. The two clips are now pretty composed without any rotoscoping although the kid layer is still not stabilized after a few attempts. I was able to track and stabilize the mountain and it seems okay. My clip is pretty much like this now throughout the duration. I'm pretty happy with it. If there's any problem, it's the branches disappearing on those bush things but I'm not gonna nitpick too much. I just need to stabilize the shot and I'm happy enough.

One thing is I suppose there's some colour correction or lighting necessary to blend clips like this. I am no colour corrector or lighting artist and I'm actually doing this for a friend. I suppose he'll find someone else to CC or such. Aaanyways.

I'm gonna try that Roto Brush as well and check those resources. Thanks



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Sigurdur TraustasonRe: Comping a distant mountain and guy close walking towards it....sigh
by on May 5, 2014 at 12:48:22 pm

hey guys,
just one two things I wanted to quickly check.

1. I'm trying to track the motion on the kid layer (one with the ground and the kid) and apply it to the mountain (I'm not sure if the mountain should move exactly like the ground, being quite a distance away, but it would certainly look better than not moving at all). The clip I apply to always jumps to the pivot/anchor point of the original tracked clip, I just want it to stay where it was on the initial frame. The track seems to work fine if only the clip doesn't jump away from it's original place.

2. The Extract worked great, only problem is the small bush that had to be there...the Extract cuts the top of the bush. It doesn't look good that way and shows that the clips have been comped together. I've tried editing the settings in the Extract effect but it doesn't get those thin strands of the bush. Just wondering if I need to rotoscope the kid to get those strands or if there was a simple way around it. Maybe just add some kind of brush strokes and track them?

Thanks everyone.


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Michael SzalapskiRe: Comping a distant mountain and guy close walking towards it....sigh
by on May 15, 2014 at 4:20:56 pm

To your first question, apply the tracking information to a null object, and then parent your layer to the null.

As to your second question with the bush, you will probably need a separate layer for the bush. Use whatever method works for you to get the bush pulled out. A luma key might do it, Roto Brush with the Refine Matte effect might do it, etc.

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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