This week we had a refresher on multichannel compositing and put the results in the basement homework, as well as learning some new techniques such as light matching and shadow compositing in what was a very big and difficult lesson!
PART I: LEARNING
1: Do not change the distortion of the original video when solving using the Distortion node, keep a separate file and name all the videos.
3: In multi-channel compositing, don’t create multiple colour nodes to process a single image (e.g. reflections), just use merge through a single grade or other colour processing node.
4: Grade node in the whitepoint value by absorbing the colour of the screen to make that colour data to zero (that is, to absorb a more average brightness of the region, pay attention to do not let the screen change too much) use gain to absorb the colour A can make the overall picture plus colour A (that is, so that the grades of the screen fused into the background) blackppint to absorb the deepest color of the object, lift to absorb the background of the deepest color, lift to absorb the background of the deepest color of the object. blackppint picks up the darkest colour of the object, lift picks up the darker colour of the background, multiply picks up a colour in the background that you want to blend in.
5: ctrl+shift selects the average rgb value in the frame.
6: Merge (divide) is the B channel divided by the A channel rgb value of each
7: After shuffle(id) and connecting to keylight, you can select a 3d part by changing screen colour
8: It’s easy to change the colour in HueCorrect, select the one you want to change and then hold down ctrl and alt to add a dot on the yellow line.
9: Toe node is to match the original screen melanin, lift to absorb the original screen is darker, you can make the image instantly into the screen (the shadow will not be too bright or black)
10: Exposure node can be used to adjust the exposure of the screen
11: Use the Specular node to connect to the glow node and select the colour A can make the colour A produce glow
PART II: PERSONAL WORK
I tried to use C4D for rendering at first, and the two images above are what went through the OCTANE renderer, don’t they look good! But alas, after my 3 hour long gruelling struggle, I failed! Because I found that the OCTANE renderer, no matter how it is set up, cannot render the multi-channel composite EXR file correctly. Sometimes there is no RGBA image, sometimes there is no ALPHA channel, and there are not many colour channel files such as SSS as well as Metallicity in the OCTANE Renderer, and many of the channel names don’t match NUKE.
The above is an example of what I’m talking about, and it’s not hard to see that there are many channels of files missing from the image on the left, many of which are black. But this is not the most important thing, the most important thing is that if I put the left file into the scene, the scene will contain the bottom and back of the tank’s “ground”, which is not what I want, I want to have the shadow of the tank, but without the “ground”.
Despite the failure, I was able to fruitfully import the wall shattering file I made in HOUDINI for the tank firing into NUKE, yay!
I then imported the tank’s ABC file directly into the SCENE node to complete this week’s stage assignment.