Category: Nuke Development

This week we were carrying on with the side tasks we were given during the completion of the garage project. I worked on green screen work and the scene of the girl in the snow.

I used the keylight node and then the eyedropper tool to remove the green from the greenscreen. I then merged the origonal scene with the background of the snow.

I then premulted the greenscreen scene which added more detail to the hair strands and set it apart.

I then needed to adjust the levels of colours emmitting on the keylight node, to make sure no details were lost of the girl and her hair during motion.

I feel like this enabled more detail to come through and it less obvious this was made from a green screen.

This week we looked at motion vectors, and more greenscreen work.

We were given homework to remove markers on an actress’ face, these are the markers you see in facial motion detectors for CG characters. To do this, i used the roto paint node which allows you to use clone to remove marks by pasting colours from directly nearby the mark is you want to remove, and painting this colour over it on the scene. I tried to make this as realistic as possible, blending the parts of her skin in and making sure it wasn’t obvious where the markers were.

I then worked on the feedback I had given to me about my garage project. I used the colour correct node to reduce the highlights on my tyre, so it would blend into the realistic CG comp more.

This week I was overlaoded with collabrative unit work, so I had little time to work on more Nuke and Maya work which I acknowledge, and will prioritise catching up on this in the upcoming weeks and over easter.

This week I needed to work on getting my garage project finished with the deadline quick approaching. I first needed to merge all my compartments of my nodes together sucessfully. When I tried doing this, one asset would become transparent. I realised it was a problem with what I was merging to what. Instead I needed to have a chain of merges that gradually introduced new assests to the scene.

I then linked my roto to the scene, and added the CG machine we were given. I added a few more colour correction and grade nodes so that this would blend into the scene more, and luckily my roto worked perfectly with the machine.

I still needed to add the smoke and shadows, but I rendered out my progress so far for my blog now all my assets, roto and machine work in the scene together.

In terms of working out the shadows, I had never done this before. Luckily we went over shadows in class this week. We were given a sphere and cast a point of light in the direction of the geometry for it to cast a shadow in the scene. We could then adjust the intensity of the shadow.

This was great, however my assets in the garage project were 2D. I had imported them as exr files from maya. I thought this would be easier for the camera tracking for me as I wanted to practice the use of cards more as a projection for objects. Luckily, we used the technique also for 2D ‘fake’ shadows which is what I would need to use. We were given the example of a paper figurine, and by simply using the multiply and blur node, with some shape adjustments on a card, we were able to create a fake shadow.

This looks realistic and would be a great method for me to apply to my project.

Work from home

This week I applied my knowledge from what I’ve learnt to finish and render my garage project.

I first added smoke with some guidance I had recieved from my teacher in class. I needed to link the smoke with the roto but invert it so that the smoke would be inside the roto, therefore inside the room. I also needed to increase the multipy slider to increase it’s intensity.

I then took the technique of the fake shadow card and applied it to my tyre and ladders. I added a double shadow for both assets, as the shadow would be hitting the wall and the floor. I made the intensities of these vary however to add realism.

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.

This week we looked at how to create a realistic CG composition, and apply this knowledge to our garage project.

Simply merging the asset to the background isn’t enough for a realistic CG comp. We looked at colour correction, as a way for the assest to blend into the scene more seamlessly. Splitting the channels to do this enables us to merge each channel and see the progess of the asset in the desired position. Nodes such as the shuffle and grade nodes contribute to colour correction of an asset.

We then looked at inputting smoke into the second room. This contained the rotoscoping we did and also working with the camera tracking we had learnt in previous weeks.

Work from home

To progress on our garage project, we now had to apply our knowledge of realistic CG composition and add some more assets to our scene.

I decided I wanted to add a tyre to the scene, leaning against the wall, as this would fit the theme of the scene. I downloaded a 3D model of a tyre, loaded it on Maya and started editing it slightly.

I made it slightly thinner and added spotlights coming from the direction the light is coming from in the scene. Then I made sure it looked okay on the render screen and rendered it out to an exr file to input on to Nuke.

I then placed this on the scene in Nuke, in my desired area I wanted it to be in.

I then had to track it to move with the camera. This was the most difficult part of this task this week as all prior ways I have done this didn’t seem to be working. After adding the tyre to the axis point I created a card on, and reading it through that, it tracked, however the positioning wasn’t right. After playing around with the card, the rotation and size I managed to get it to look right. However, the the tyre needs more colour correction and a shadow to blend. I added a grade node and adjusted some colour gradients, as well as changing the input to RGB instead of linearr, but it needs more focus on colour correction and shadowing.

I then used the same approach and template to add two posters on the walls. I decided to add mechanical posters to suit the theme, however these need shadowing as well. I have slightly changed the gain on the grade node of the white poster, as it is slightly out of the light, however the black poster seems to have the appropriate colours and light gain for where it is placed.

This week we looked at seperating and linking ‘passes’ within an image on Nuke. This means all the seperate nodes such as grading, diffusing, specular and refraction nodes. We can see what goes into making up the image. If we pull up the lens contact sheet node we can see all of the changes the image has gone through and how these come together.

By changing the colour on the grade node to red, we can see what part the grading affects the image overall.

We then looked at a more complex and varied version of a lens contact sheet. This time, with an image of a car. We can see different effects Nuke can produce such as a UV screen and a wireframe image.

We then took the 3D image of the car, and looked more into UVs on the 3D viewport. Through using the nodes shown below we were able to see the 3D model of the car in a UV lens, and through an inverted black and white lens.

Work from home

After some guidance from our teacher, I was finally able to complete the cloning and clean up on our garage project. I realised after advice that I was not using the 3D card node right. I needed to create cards from the tracking points, and attach these to the scene. I was then able to roto around these and sucessfully make them disapear and blend in with the background.

Then, again with guidance, I also resolved my roto of the wall problem. I used a correct template to follow the correct nodes, and again I was using the card incorrectly. I also needed to add back the lens distortion, perfect the tracking by adjusting the points at some frames, and then this roto tracked with the camera.

This week we looked more into projections, and 3D techniques in Nuke.

There are three common ways projections can go wrong in Nuke; smearing, doubling and resolution. Here are some examples of these.

We then looked at changing lighting, from something that seems filmed in the day to a night scene. To do this, colour correction is key. With changing the saturation, hue and colour grading you can create a more night lit scene.

We then need to add light sources such as lighting nodes, and change the direction of these. We can also make artificial lighting from the lamp for exaple. To do this we need to add the glow node, and animate the blinking effect using key frames. We can also changethe colour of this artificial light source.

We then looked into creating a 3D space out of geometry drawn on a scene. To do this, we took the model builder node and created a card, we then shaped the corners to the shape of the wall on the building. Then, we went on edit mode, selected the edge and extruded this all around the scene for floors and walls.

When we then looked at this on the 3D screen we saw a 3D card scene of the perspective and shape of our scene.

Work from home

This week I worked more on my garage project. I worked out that I was creating an axis node from scratch, for the cone to track along with the scene and camera I needed to create it from the tracking points on the tracking camera. I re tracked my scene with 500 features instead of 200 and learnt the way to connect the axis and cones through the points on the floor through the pre made script.

This way we know match move is working.

I then rotoscoped the wall surrounding where we would be putting our model, again I am having trouble with the tracking which is something that is my next objective to figure out in the coming week, as well as combating why the clone tool won’t work for me so I can get rid of the markers.

This week we looked more on the topic of inserting 3D geometry on to scenes, and 3D scene tecniques in general. First, we practiced this with inputing text and a colour wheel on to a wall in a 3D scene. On the 3D screen viewport we can move these around easier.

We then looked at more clean up tecniques, but this time on a 3D scene. We were shown written instructions and a before and after of what this would look like sucessfully.

We continued to look at tracking a 3D scene, in the 3D viewport you can see specks of the scene tracked out and the points that were sucessfuly tracked.

We can then turn this into a ‘Poisson mesh’, creating geometry of the 3D mapping.

However, if you create a group and bake this, we can see the group of points created and the 3D scene through these points, the shaping of it from a 3D perspective.

We then went over how to create a plate, and did a quick planar tracking on this scene. This taught us how to create geometry on a 3D scene and how to transform it within this scene.

For the first lesson of this module, we went stright into looking at advanced tools for VFX within Nuke, with looking at Nuke in a 3D perspective. So far I had only been using nuke in 2D so this was a new development for me,

First, we looked at lens distortion. We used a checkerboard image as this was the most simple way to process what this node could do, as it was only working with striaght lines.

Here we can see it has detected the straight lines when we click detect, but they slightly are distorted at the sides by curving.

When we click ‘solve’, it strightens these lines to create a flat surface of the lens, as we can see the change of the lines in green.

We then looked at the 3D function node ‘Scaleline render’ in nuke by pressing tab on the viewing screen, on a scene with the moon.

In this function, we can add a camera, and select this on the viewport to see through the camera’s lens.

this means we can render out a 3D scene of models through these, and adjust where they are on the axis.

We can add models through the ReadGeo node, and therefore render these out through any angle, and even animate the camera’s movement around these.

In the 3D screen we can also add lighting, adjust it’s placements and colours in which it inputs onto the 3D scene we create.

We then looked at camera tracking within an actual scene, and how this camera tracking can be used as a 3D feature within nuke. We were given a scene of a street, and camera tracked a specific part of the scene, We could then increase the amount of features, or points, in the scene that the camera was tracking. We increased the amount of features to 1000, so many points of this scene were tracked as it moved.

When pressing track nd solve we see the completion of the tracking of these points in motion when we go through the scene.

We can create solid shapes to appear on our scene, we used a checkerboard plate as an example. We could rotate it’s position by swiching to the 3D screen, and moving it within the scene.

When you press tab and swich to the 2D scene, you can see these appear within the scene of the street.