In Nuke these weeks, we learned about removing tracking dots, motion vectors and re-matching grain to create proper comps in Nuke.
We started with learning simple regraining when comping things in or out of shots, this would entail making a denoised plate of our shot then using the noise difference beween our shots and applying this on to our comped areas.
When we do our rotos for a scene, we use a frame hold to freeze our paint and make it not move around, but since at this point it would be a static image, it needs grain reapplied to make it look real
If you want to get your noise to match the original plate, what you’ll do is merge the denoise plate and the original with the operation set as merge, this will give you this result, only the grain that was minused or removed from the original plate.
After this you use a tracker and a transform match move to get a track of your patch to place overtop of the original.
There were two ways to regrain this properly, one being re-graining it through the above state method of getting the original grain, then using a merge plus and keymix to put it on my patch.
The other way of doing this was using an F_Regrain to get a sample of the original grain for the patch and then merging it to create the grain that way.
After this there was 3 ways of reviewing the grain implementation to make sure it looked real, these were using a blue and merge with a grade, using grain check and using Qc Technical to check the edges of our patch.
After this we worked on comping in something and replicating the lighting data and luminance on to a patch. We did his by using a curve tool and keying the luma data to a grade node. This would give us our luma values and keyframe them into a grade to allow for light flickering.
After this we went about doing tracking on a face to remove facial markers and add things on to aface.
I Struggled a bit with getting the operations to work on the painting but managed to get it working after getting a proper alpha out of it.
After this we learned about using UV maps, as they can be used to distort in certain ways and are a way to organize a texture and image and modify it later on.
Using the smear tool i managed to disrupt the UV and make the texture non linear.
After this we experimented with using Motion Vectors, which would help a lot with doing the tracking on the facial dots.
Next i did the homework, which involved adding in two things on to the face and removing the tracking dots.
After a lot of tweaking, i realized that both i had a regrain where it shouldn’t be and a premult where it shouldn’t be, and managed to get a decent cleanplate working.
I had some issues with the face warping hard, but it was because i didn’t have my input frame set to the correct reference frame. After this i applied some vector blur and reapplied the grain and it looked much better.
Overall it could use a bit more mixing on parts of the face to look more realistic but it works as a proof of concept and learning motion vectors.