Replace background or what?

Mocha AE
#1

How this possible create such a video with Mocha?

Author says , he used a lot of tracking points on their bodies.And no more information.

Maybe i can understand tripod shot , just track the part of body , mask out, and then replace backround.

But how work it in moving camera shotings? how replace background? or this is other technic? Do you have idea how to do it?

(sorry, i’m not good in English)

#2

Yes, the artist here is doing a few things.

First of all, he’s using actors over a lot of PLANAR data, notice how the backgrounds can be broken down into simple planes.

Secondly, he is using the remove module to make cleanplates of the shots where there are no actors.

Then he is compositing the actors back over the cleanplates with rotoscoping.

And finally he is freezeframing certain parts of the shots (like the boy against the tree or the guy at the top of the slide) and compositing those frozen frames back into the shot so he can use them as a starting point to slide their legs away.

So he’s using mocha Pro’s remove module, mocha rotoscoping, and a compositing program like AE or Nuke to get this job done.

Please let me know if you have any more questions and I will be happy to help you.

Cheers,
Mary

#3

Yeah , thank you.I watched tutorials about “remove module” and tried to do it.But i saw such a bad result. I tried “linear”, “blend”, “increase edge width” , just like on tutorial on your youtube channel.but didnt solve this problem. and my “remove” layer is always inside “floor” and “wall” layer. what can i try different something that solve this , and result perfect?

why mocha takes wrong parts of frames or insert wrong ?

 

#4

And 2nd question , do i need to set planar surface and adjust of “remove layer”?

#5

It looks like your floor track is not correct, so that’s why you’re getting poor results. Your wall track looks just fine, the floor needs work. I think if you make sure the track is rock solid it will work for you.

If not, you can send me the shot and I will take a look.

Cheers,
Mary

#6

Look at it please .(it is the part from the clip that link above(1:06-1:09 ) )

 

ooopss)))) i saw tracking gone wrong between frame 28-40))

 

 

#7

OK, see what I mean about the floor track? Look at the grid, it’s shifting rather than being glued to the floor. Also, you may be leaving some shadow from the girl on the ground, which will definitely cause problems in the remove. Shadows are also occlusions, even though they are transparent.

You also need to go into the clip tab and crop out the black bars in the screen. Simply drag the yellow dotted lines in the clip tab down to have mocha not look in the black bar area.

So…

  1. Crop Black Bars in the CLIP Tab
  2. Roto around the shadows from the girl more in the TRACK tab.
  3. Fix the ground track in the TRACK tab.
  4. Try to render again.
#8

Yeah.Thank you very much, i will do it all, and back again.

#9

I have now better results but not satisfying.

First problem is the , appearing perpendicular lines in the ground (in about first 15 frame) like sweep.i showed it in video and the image below.

2nd problem is the sharp transition on the wall layer.i though it is due “blending option”.but it helped just 1 frame , rest of frames was with problem.I used “über”.

 

 

#10

and when i tried to do “Linear” in Illumination module, i got such a result.why? i didnt understand theese.

 

sorry, if i give more questions :slight_smile: i just want to understand Mocha deeply :slight_smile: and do great works :slight_smile:

#11

Hi there,

It may be that there’s too much contrast to do lighting modeling well.

ILLUMINATION MODELING:
“NONE” simply replaces the pixels that move behind the object with no lighting changes
“LINEAR” changes everything in the single spline based on the Hue, Saturation, and Value of all of the pixels around the spline, so this contrast in this image might give poor results for the size of the remove shape.
“INTERPOLATE” looks at the HSV values all around the spline and tries to match the pixels inside the spline with a blending of those outside edge values.

Because of the size of your remove shape, you might need to comp the new cleanplate over the top of the image and do some hand color matching. The remove will not nail every single shot 100% every time, often compositing is needed to fix any errors. It still will save you time in the long run though.

Cheers,
Mary

 

#12

Please lets again , step by step explain to me, “problem 2”.(where i draw blue color). if i use blend and linear why such a problem in the wall?

(i’m not perfect in English, thats why i cant explain and understand perfect) :frowning: please step by step clear :frowning:

#13

The bottom line is that you might not be able to get the results you are looking for with the cleanplate from the remove alone. That is what I am saying. You will need to do some compositing to final the remove work.

I am not going to be able to explain this better than a video if we are having a language barrier, so let me link Martin’s videos.
http://www.imagineersystems.com/videos/basics-of-the-remove-module-with-mocha-pro-part-01/
http://www.imagineersystems.com/videos/basics-of-the-remove-module-with-mocha-pro-part-02/
http://www.imagineersystems.com/videos/basics-of-the-remove-module-with-mocha-pro-part-03/

Our documentation goes over the remove module in depth, step by step too: http://www.imagineersystems.com/support/documentation/#Mocha_Pro_8211_The_Remove_Module

To fix these small errors by hand…

  • You will need to render what you have.
  • You will need to take the render into a compositing program with the original plate.
  • You will need to composite the new mocha remove render over the top of your original plate.
  • You will need to use your mocha shape you used for the remove as a mask on your rendered remove layer.
  • You will need to feather the mask.
  • You will need to do some hand color correction.
  • Match the grain on your remove layer to the original plate.
  • Render your final shot.
Do you see what I mean?

Cheers,
Mary

#14

I understood you completely.I watched all these tutorials.And read the documentation.Final question and i go to the experimentation.Is it important to do right planar surface and grid on the remove layer? Thank you very much for your patience :slight_smile:

#15

It’s not important to lay the grid and surface tool out perfectly, but the remove needs a rock solid track on the BG layers in order to remove properly. :slight_smile: No worries!

#16

Can the Rotobrush in Adobe After effects be used in the mocha tracking system

#17

No, it can not.