This week’s focus is on making the work of the Machine Garage. I didn’t use the teacher’s machine material because I had some different ideas. Since there were a lot of bricks in the video, I thought of the door of the Diagon Alley in Harry Potter. I wanted to synthesize a door like this in the video. In maya, I make models and animations to get the material I want. Then I import the rendered images into the nuke file I made earlier to do 3D tracking and color blending. Although there are still some problems to be solved, I’ve gained a lot of experience with 3D tracking in nuke.
The content of this week’s class is to modify the figure in motion. We need to use the smartvector node to track the movement of the portrait. Through this function, we can change the portrait at will, such as adding tattoos, scars or removing moles on the face; at the same time, these added materials can also follow the movement of the portrait to change.
Process
But I had some problems when I was doing my homework. If the motion amplitude of the portrait is too large or the time is too long, the added material will deform greatly, resulting in failure to modify the portrait. At the beginning of the video above, the woman’s moles are removed. However, after frame 50, there is an obvious deformation in the erased part. I have tried many times and failed. So I used the method of roto to remove moles from women’s faces.
Process
I had a similar problem with devil man. But I watched some tutorials, and found that we can adjust the parameters of the smartvector node to adjust the tracking of the portrait’s motion. Although there is still a little bit of the above problem, it can be mitigated by choosing the right number of reference frames. In this video, I made this man’s face look like a viral infection or burn; at the same time, I put fire in the man’s eyes.
This week’s lesson is again about green screen picking, but it is different from the content of last week since the material of the woman has more details, especially the flowing hair. We need to adjust more different appropriate keylight, and extract the color around the hair in order to achieve more detailed hair.
Green screen is one of the key features of nuke. We can use the Keylight node to extract the color of the areas which need to be erased, such as green screen; at the same time, we can adjust the different keylight nodes according to the details of the materials, and merge them to get a fine image. Then we can add additional material to the blank area.
We learned more about how to use 3D tracking to add footage to a video. I found a lot of materials of flowers and vines to modify the whole space. Because the space in the video is like a square, and the camera has an Angle rather than a level view; as a result, I need to adjust the card exported from the 3D tracking points to fit the angles of different areas in the space, and add shadows, in order to make the materials be more natural and reasonable in the overall view. I feel like I’m making progress, but I’m still looking into more features of 3D tracking.
This week, we’ve focused on how to use 3D renderings to make color adjustments in nuke. First, we have to use D software to render exr images with multiple AOV channels , such as beauty, specular, shadow, and crypto object. This part is very important since these AOV channels have much information of color and rendering, and allow nuke to get the most out of it to get the best visual effect in the film. At the same time, if we put all aov channels in one material, we need to connect the node of Shuffle to export the aov we need to use, and then connect the nodes of Grade or Colorcorrect to adjust the color.
This week, we used 3D tracking to make some changes to a scene in a video. I added flower textures on some walls, and changed the blue doors to be a green one. In this process, I found that not all tracking points could perfectly match the camera’s movement, so we needed to find the right tracking points to add materials.
The main content of this semester is how to use 3D tracking in nuke, which is a very important feature in nuke. We can create three dimensions for a scene in a flat image to track any area of the scene. 3D tracking can track cubes as well as planes. This function can create many tracking points and describe the structure of objects in the picture with tracking points. Through these points in the space, we can achieve a virtual camera with the same motion and other attributes. If we import the points in these Spaces and the calculated camera into the 3D software, we can create 3D objects, and the camera can be used for rendering. The rendered objects will be correctly matched in the original picture.
