Learning Nuke

So far I have been following the book Nuke 101 which has been pretty handy as it supplies exercises on a CD. I’ve been following each chapter although I may skip what is irrelevant to the project.

To begin with I was trying to get myself familiar with the interface as all software can be initially daunting. So far I’ve found it quite simple due to the fact that Nuke is node based so everything is visual. Maik had briefed me a while ago about the software and how the advantage of it is the fact that he doesn’t need to be by a computer to plan out his node flow. If he has an idea he can draw the flow in a notebook and take that to Nuke to fully realise it. Furthermore, he said that if he takes a photograph with his SLR camera, he can put in the settings he used for the photo into Nuke, much like V-Ray.

The above print screen is evidence of me following Chapter 2 which teaches about Basic Compositing. Through this simple node flow I’ve managed to learn about each node:

  • Read are the images/video clips you’re importing into Nuke
  • Sometimes the images you load into Nuke are straight and will have to premultiply. For example, the doll influenced the background because it was a straight image and therefore had to be premultiplied.
  • Grade node is the colour correction which you can only do to a straight image, hence why it has been placed before the premult node.
  • The Transform node deals with the size, position, rotation, etc and must be added after the premult node.
  • Shuffle deals with the channels. In the print screen the mask was in the red channel but it had to work across all channels in order for it to be effective and the Shuffle node allowed me to do that.
  • Merge enables you to merge nodes and in this example that means combining the foreground and background.
  • Write node is basically rendering the scene.

All this was pretty simple so far.

This is the result from Chapter 3 where I learnt how to make a more complex node tree. This was actually quite difficult for me as I’ve not handled render passes in the past since we’ve always just rendered it straight. I’m also not very experienced with lighting and although I know some of the terminology, I still have trouble quite understanding it.

Another problem I encountered seemed to be the actual book’s fault. I spent the night and most of the next day trying to make something work but it just wouldn’t do. It was only when experimenting with other options and talking to Deon that I realised it wasn’t my own error, but that of the book’s.

As you can see at bullet point 8, it says ‘choose Avs Intensities’ although that alone is a typo since it should be AvG Intensities as illustrated in the image above. Remember, the image above clearly says Curvetool1 (Avg Intensities)

A few pages later it changed to CurveTool1 (Auto Crop). It was having problems getting the Auto Crop Animation attributes to turn blue or to change over each frame. It was suppose to be Auto Crop, not Avg Intensities.

I’m still trying to understand this chapter better by going through it again and reading it properly. I didn’t want to just follow it and not understand the reason for it.These are a few notes I’ve taken down in my notebook despite the fact it’s already in Nuke101 as I want the information to sink in:

  • Render passes are always premultiplied, so you have to unpremult all passes to colour correct. This explains why on each branch there is always an unpremult following a Shuffle node. For each Shuffle apply each respective render pass in the properties. Plus = Add which means you’re adding (name of render pass) to the composite.
  • Lgt is set as the background of passes.
  • Shuffle, Shufflecopy and copy reorganise channels into a single branch to ease image manipulation.
  • Shufflecopy takes two inputs.
  • Shadow is a subtractive pass so you set it to minus. You’re taking light away.

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