Category: Nuke Term II

I had difficulty thinking about what I should add to the video. Then I went with the flow and added one effect following which things just started unfolding. 

First, I added the snake texture to the face, I had some problems with the texture because it was stretching when the character was moving. I fixed it by roto keying the texture. For the texture, I didn’t add a frame hole. One more problem that I faced was that when the face was moving, underneath the texture, light would pass through it and I didn’t quite know how to fix it.

Next, I moved on to tattoos and Jacket patches. These were fairly easy. While merging with the main plate I used the operation stencil and this helped and the light didn’t go behind the tattoos. The only downside is that the image becomes black. 

The class was started by Gonzalo explaining the importance of regrain in your plate and how to work with them. We saw 3 different alternatives. The first one was to use the minus the original plate and the denoise. The second way is to use a regrain node. The third way was to use a new gizmo and this was now the standard in the industry, it’s called DasGrain.

Patching was the next thing we learnt. We had learnt how to fix the patch and cover them up, but it was on a balanced light this class was about how to cover them up with uneven lighting. We saw different ways to tackle it. High and low-frequency, image frequency separation help to preserve details and later reuse the details during cleaning. To get the low frequency we use blur and to get the high frequency we use from, then use plus to marge them. 

The next method was similar, but this time we used the divide and multiply, we use only one roto paint and we can use the blur to control the light.

The final method was to track the point you want to patch, then use blur for the premult and the patch and then divide them, and then multiply with the patch. Later grain the back and over it with the plate. This way the patch will move with the track and the light will move with it.

The curve tool helps to match fluctuating colours or remove a fluctuation, what I mean by fluctuation is any kind of light. How this tool works is, first to select the region to match, this could be the whole frame or a part by rotoing it. Then hit the ‘GO” button to analyse the range. Next copy the Maximum and Minimum Luminescence Pixel Value and paste it into the Grade lift and gain. Then added Grade to the plate which has to match the light.

The next way we saw how to clean up the patch was easier and quicker. First roto around the marker, then transform and move the plate a little bit so you can hide the marker. Tack the point and past the value to the roto. Oremult and merge over the original plate.

The next method is the same as the before one, but in this, we use roto paint to do the patchwork and roto around the marker we need an alpha to cut out the region with which we cloned. 

InPaint is the best way to work on patch removal. First roto the area you want to patch and track it. Matte to InPanit and make sure it is on Matte Aplha then adjust the setting. Added the grain to the patch, copy the alpha of the patch to the alpha of the regrain and premult.

Before going to the motion vector, we saw the Expression node and how to use it and learnt more about UV. 

The Smart Vector node calculates all the pixels which have moved and produces a video which later can be tracked in Vector Distort. The Vector Distort has different output options the default is Wasrped Src, this potion is too heavy and might slow the project. Next, the St-Map option is lighter than Wasrped Src.

Last week saw how to despill images, and this week’s class started by showing us how to protect areas where you needed to keep the green, for example, if the actor is holding a green bag or the acter eyes are green. To protect this we can use marge operations in this way.

Minus: by minus Original from the despill plate you get the luminosity lost by removing green.

Multiply: the background over those luminosity values.

Plus: it is over original to add a background in the transparencies.

We can also, use the saturate node to desaturate and this help to remove unwanted colours.

Add Mix was a new node we used in this class, Add Mix works like a marge but with Add Mix, we can control the alpha from both channels by utilising the graph.  

Additive Key is not a node but it is an image-blending technique used to recover fine detail in difficult areas such as hair, soft transparencies and motion blur, edge treatment and despill can create very good results to better integrate your plate to the background Additive Key manipulates lightness values in the fine details and adds it to the background under the foreground plate. To create this you need to take an average of the plate by using a constant and then minus it with the plate. Use the Saturation to despill then use Grade to adjust the alpha, and then Merge to the background.

Sometimes when working with greenscreen we might get lucky by getting a clean plate, which means a plate only with the background. This helps a lot when you get this because we don’t have to do IBK and just use divide and multiply to remove the greenscreen.

In the next, we saw how it affects only the ages of the hair to get more of the dilates. By using the colour Lookup node we can control the RGBA to only affects the particular area. Then mask we can mask it with a roto. Mask to the grade and adjust the transparency.

we also saw how to make take alpha from an image without using any key, but this way take an average of the greenscreen and then the difference it with the plate.

Edge Smearing Gizmo, help to restore the edge of the image. This gizmo works better than Edge Extend and is softer. Next, we saw how to make our own Gizmo and I felt this was very helpful for making our work easier.

For the next few weeks, we will be taught about greenscreen and the best way to remove it by using a nuke. This week’s class is about the bases of greenscreen.

The class started off by explaining to us about RGB and HSV, we all knew what was RGB (red, green and yellow), but HSV was something we were not sure of. The HSV which stands for Hue Saturation Value the scale provides a numerical readout of your image that corresponds to the colour names contained therein. RGB can also tell us about the HSV, its broke into.

R = HUE: Hue means colour

G = Saturation: Saturation pertains to the amount of white light mixed with a hue.

B = Luminance: Luminance is a measure to describe the perceived brightness of a colour

By using the RGB and HSL the keyer node ( AKA Luminance key) crates alpha for an image or a video. The node also has different operations like a red key, green key and blue key. The keyer has a range which is a graph where you can control the range of the area getting affected. 

Next, we used a shuffle node to isolate colours, for example, we used only one colour like red in the input and for the output connected to all the other colours but not the alpha. Use merge to minus different colours from each other. Using the same technic we remove an area, by just adding an Add mate node and keeping the value at 1 and adding an invert node. Adding a roto can help to affect only one area. Doing this helps to change the colour of an area and it’s easier to roto.

Nuke has a lot of options when coming to keys like:

 IBK Colour and IBK Giamo: IBK stands for Image Based Keyer. It operates with a subtractive or different methodology. It is one of the best keyers in NUKE for getting detail out of fine hair and severely motion-blurred edges.

Chroma Keyer: tends to work better with more evenly lit screens that are more of a saturated colour. NUKE’s chroma keyer is that it takes full advantage of any GPU device you have in your system over the other software.

Key Light: It is a really great keyer overall and does colour spill.

Primatte: This is a 3D keyer. It uses a special algorithm that puts the colours into 3D colour space and creates a 3d geometric shape to select colours from that space.

Ultimatte: keys that are good to get detail and pull shadows and transparency from the same image.

Despill is prose when you remove the green which has reflected on an object. When the object standing in front of the green scene the skin reflects the green colour. We can use IBK or the Keylight to despill. 

For homework, we had to add an image by removing the green screen from the video.

This week we saw to add a CG object to a plate and how to colour-correct to match it to the plate. So we have to complete the garage for this month and we need to add artefacts on the walls and or the floor.

Gonzalo started off the class by going throw what we have done with the plate and how we have achieved it like, match move and clean up and roto. Then moved to a basic grade match, for example, we took 2 different colour plates and match the colour of one plate to another by adding the grade node under the plate which you want to change the colour for then selecting the white point from the main plate then selecting the gain from the plate you want the colour from while picking the colour you make sure you press the command and shift. Then we tied the same things with a different plate but this time we used the black point and the lift.

There are different parts in the nodes and Gonzalo took us over all of them and their use. The first stop was the Master CG CC.

So we started with the basic grade match with the help of grades before we start messing around with the Multipass, following the same process we did on top. While picking up the colours you should make sure that you pick not from the darkest or the brightest. We used these nodes to do the basing colouring.

Next was Multipass Comp, the 3d moulded was rendered in Arnold so it was Armold Multipass. The main thing about this is that, if you only needed to change something then only change it otherwise you should not teach it just because you have the option to. For this, we just changed only the specular direct and specular indirect, so that the machine refutation is lowed and as a glow to it. We use the Plus to merge to add them.

After that came ID and adding Re-texter, first we select the area to which you want to add the texture then get the key light tool and invert. make a Shuffle node then give it to STMap secure and make sure that the channels are on RGB not all, for the texture add grade and do the grade match then added a copy node and then premult then before the texture plate is added to the Master CG CC add a Multiply so that you control the effect on the texture.

Next was the shadow, which is an important part of the CG it gives a feeling that the object is not flowing or not there. So whenever you. added a shadow you needed to use multiply for the merger. We used the AO in the Shuffle and Shadow mask and the Shadow Matte added the shadows

Relighting, we used the Normal pass and the Position pass passing it to the PP mask hub this helped to get the alpha for the object using screen merge giving a grade to light it up.

Motion blur, if you have the Motion vector in your render you can do the changes on that otherwise, put a remove node but the optraion is keep that passes to the motion blur 3d plugin the camera added the vector blur. Added Grain and the Chroma aberration and defocus to make sure that the CG match the plate exactly. Using the defocus node we did the defocusing and added the remove node and naked to keep for the grain, we used the Grain node and matched the RGB add the keymix.

For the homework, we had to add more artefacts on the wall and the around the plate.

This week’s class was about CG. We saw different channels. For now, we get to use RGB which is red green and blue but when you render in 3d software we can add more passes. This help to get better control over the highlights, mid-tones and shadows. A rule of thumb is whenever you’re following to rebuild the CG asset always use “plus” in your merge for lights and always use “multiple” in your merge for shadows.

There are different types of AOVs (Arbitrary Output Variable)

Material AOVs these used to adjust the material attributes or shader of objects in the scene like using the passes so you have control over highlights, mid-tones and shadows. 

With LightGroups, we can adjust the Individual lights from a 3d scene.

Data Passes also known as Utilities, in combination with these tools can be used to achieve various effects like defocus, motion blur, re-lighting, and many more.

IDs help to select an area

The layer Contact Sheet node lets you view different passes on one screen. 

Different renders from different software will be having different passes so when changing any highlights, mid-tones and shadows you needed to back it up by using a shuffle node.

We can add UV texture in Nuke with the UV passes, by rendering the geometry. You start with your geometry then add whatever texture you want directly to the scanline render. The other way is to add UV geometry scanline, render it and then to STMap to stamp channel and add the render src for the texture 

The position pass represents the 3d scene in colour values. Red is the x coordinate, green is y, and blue is z. You can use a PositionToPoints node to visualize it in the 3d space. A depth channel stores the distance from a point in 3d to the position of the camera (and will be moving with the camera).

PP Mask hub is a gizmo in which you can select a part of the plate and with the help of a position pass and relight an area, it is a simple way to do it and this also can be done using a normal pass.

For our homework, we had to add a car to a background of our choice and match it to the background.

This week we saw an advance projection.

We saw simple way of using roto paint, first we needed to find a reference frame, then add a frame hold node, then do your roto paint and under the paint add one more frame holder. Under that, added a premult, after which the 3D project node for the projection’s camera, added a one frame hold on the same frame, then pass the camera from it. Added the Scanline render add a camera without the frame hold, at last merger it with the plate.

Gonzalo showed us the importance of taking the right reference frame. Without the right reference frame, the projection comes out blurry and pixelated. If you see the small door we can see the differences between taking the wrong and right reference frames.

The next thing we were taught was how to project twice in the same areas.

We also learnt about different types of Projection Artefacts

Smearing: The image looks fine from one angle but the image smearing or streaks across the object.

Doubling: This is when the projection multiplies in the geometry.

Resolution: Not enough resolution in the painting because the camera gets too close.

We learnt how to change a scene from day to night, but the important thing was how to zoom in or out with the parallax (the motion of things close to you moving faster than those far away). 

As our homework assignment, we had to roto the wall and remove the tracking points in the Garage video and add some stickers or drawings on the Greece street video.

This week’s class was about 3D tracking and Projection, the project3D node projects an input image through a camera onto the 3D object. Firstly, we saw how to project texts on a video by using a card node, scene node, camera 3D node and scanline render node.

For the 3d patch – project on mm geo, first we need to find a mind point of the video and add a frame hold node then use the roto paint to do the cleanup, add a roto and use it on the cleanup areas so there won’t be any problem in QC We then have to give it a bluer on the edge to blend it in and add a premult, following which we add one more frame hold on the same frame. So now to project the clean-up in the moving camera, we needed to add a project node, card noes where the projection is taking place in the scene then a camera and scanline render, so in the project node add a frame hold on the same frame as before then attach a camera to that then to the project where you needed to attach the camera attach the 3D project to the card, card to the scene then scene to scanline render also added the camera to the scene and scanline render.

3d patch for project roto, from the plate, plug it into project3D then add a card at the area where you want to do the roto, plug the project3D at the cared img input, under that scanline render then roto after that project3D to revise it then copy past the same card from the top, one more scanline render, for the first scanline render just add a frame hold then for the project3D later gives the same frame hold for that last scanline render just add the camera without frame hold.

Project UV was fairly easy to understand than others, from that plate you needed to need to add project 3D then a card for which area you want then added the scanline render for that reader on the background. Add a square for changing the layout added your roto pant to do your clean up then change the settings to lifetime then premult it and add a reformat then copy paste the card from the top then scanline render and merge it with the plate add a camera to the project 3D and the last scanline render

Point cloud helps to visualise the video in 3D space so that adding an object or a card will be easy and you will know exactly if the object is teaching the floor or the safaris.

Poisson Mesh helps to visualise the video in 3D space and converts the point cloud to geometry.

Baked Mesh from pint cloud, to create this you need to change the select node to vertex and then select all the points from the point cloud then go to groups in the point cloud then create a group after that select the group then bake select groups to mesh this helps in geometry also. The other one is Bake select group this helps to understand where is your card placed in the 3d wold.

To work with the Model Builder geometry node, we need to add the camera and sounds to the node following which we go in the node and then create a card to match the corner with the object you want to cover and treat it as it is a corner point then play the video if you feel that it is going off the place move it to match it again.

For homework, we had to prep the room and then place the trackers and the grind.