We have been exploring the process of green screen removal, which involves extracting the green background from a video and replacing it with other visuals.
One of the techniques we have covered is the use of the hue correct node, which enables us to remove the green color from our footage by creating a node graph. By selecting the green color in the graph and dragging it down, we were able to effectively remove the green screen from our footage and prepare it for the insertion of other visuals. While this technique may seem relatively straightforward, it can be a powerful tool for creating compelling visual effects.
We also explored the key luminance node, which can be used to selectively affect certain areas of an image or video. This technique involves creating an alpha image and selecting the specific areas that we want to modify.
During our lesson, we experimented with this technique by selecting only the sky in our footage and adjusting the levels at which it was selected. This enabled us to fine-tune the visual effect to create a more natural and realistic result. Overall, the key luminance node is a valuable tool that can be used to create a wide range of compelling visual effects.
We explored how to adjust the lighting in specific areas of an image or footage. During our lesson, we used rotoscoping to isolate the particular area we wanted to modify, and then applied various nodes, including the shuffle, grade and keyer node, to enhance the lighting and make it appear brighter, we used this example of a snowy landscape to make the bottom half more light.
We then looked at creating rays of light coming out from behind objects such as trees. This enhances the lighting apparent behind an object. This was done by using a node called volume rays, along with the selection of just the tree using rotoscoping.
We also learned a basic technique for creating a blurred effect in a specific area of an image using rotoscoping. This technique involves using an image to create a rotoscope of a circular area, and then applying a blur node to that area. Finally, we merged the two to create the look of a blurred circle in the specific area of the image.
Work from home
For the garage project I felt like I needed to add another big asset to the scene.
I decided to add ladders to fit the theme of the project. This also fit in well with my other assets such as the tyre and the mechanical posters. I downloaded a 3D model of four ladders together. I then added the texturing in Maya adjusted the placement of the ladders.
I then rendered these out and added this file to my Nuke garage project script.
I then followed the same method I had used on my other assets and tracked these ladders through the camera tracker, and then synced this up to the scene. Again, I used the axis on the wall I wanted them to stay against and then created a card which I then linked to the original image of the 3D models. These then successfully tracked with the camera and moved with the footage.
I then had to do the homework we were given which was linked to the green screen methods we had been using. I first tried using the hue correction node and the keyer node to adjust the levels of permittance. However, this was picking up on too much green in the image.
I decided to use another method we were shown for this task.
For this I used the Keylight node in which you can select a colour using the eyedropper tool and adjust how much of the levels you want to be removed on the footage of this specific colour. I selected the green on the green screen and adjusted the numbers until it was at a level of green removal that looked professional.