Creating lightening flash with curve tool

For this (Below) shot from Valiant I was asked to add some lightning flashes in the clouds. Thought about it for a second and realized I am not the best animator so i turned to the curve tool.  

First thing I did was go to youtube and find reference that I liked. I picked this video.

I brought my footage into nuke from youtube hooked up the curvetool and picked an area I liked.

I added the time offset just to get the footage to frame 1.

Picked the area I liked for the curve tool to calculate

Then I hit go in the CurveTool tab and let it calculate.

Here is the image we will add the curve to.

Added a keyer to my clouds background to create an alpha of the area I wanted to have effected.

I copied and pasted the CurveTool Intensity Data tab into an exposure node in all three channels RGB.

This was my result!

You can also change your keyer to get different results or add an expression to the exposure tool to make it brighter or darker.

simple expression multiplying it by 2

Nuke Curve Tool

The curve tool is great for a few things. I am going to show you how to use the autocrop feature of the curve tool.

The curve tool is under the very first tab in the nodes panel in the image section.   You can always hit Tab and type curves and it will come up.

What the autocrop feature does is it looks for an alpha then crops your bounding box to fit the alpha channel. This can save some time in render and just over all workflow. 

 

Below is the same image but its alpha channel and bounding box.  

Alpha Channel 

I hook up the curve tool to the node I want it to analyze and under the curve type I change it to auto crop then click go!

Once it is done analyze you will get a data set under the AutoCropData tab.  

Now all you have to do is add a crop node and hold command/ctl and click the animation menu from the curves animation menu to the crop animation menu.

Here is our new bounding box! Now instead of reading a 4k or 2k plate for the whole image it will only update what is in the bounding box! 

Here is what my end result nodes look like. 

This trick can save you a lot of time when using large images. Sometime it can also take a while to analyze so you have to figure out if the analyze wait is worth the end result. 

Nuke relink

I have seen a few gizmos that relink your read nodes in nuke. I prefer to use a StickyNote, that way I don't have to rely on anything being installed if I switch to a new computer. 

Create a StickyNote and in the name field type filepath . In the label field type your file path to your project mine is: volumes/SSD_Video/FISK/Fruitvale. My computer is a mac so I have volumes/. If you have a windows machine this could be D:

As a work flow I usually create a couple of StickyNotes and copy and paste the text from one to the main StickyNote.  So I have my home computer which the label is work/work/ and I have my work computer /SSD_video/Fisk. When Im at home I paste the work/work/  in the main StickyNote and vise versa when I go to work I paste /SSD_video/Fisk.

Now all you need to do is and some text into each read node you bring in. 

In the read node add [knob filepath.label].  This path is a continuation from the StickyNote so really your path is split in half. First half on the StickyNote then the read node picks up the other half. So [knob filepath.label]   is taking the place of volumes/SSD_Video/FISK/Fruitvale and files it in from the StickyNote. 

Lesser of Two Evils

WE have been working on a project called CXL for a few weeks now.  In those few weeks we have shot some greenscreen footage for the film on the Panasonic hpx500.  The director Sean Gillane explains to me that this is more of a broadcast camera and not the best for Greenscreen extractions.  We decided to give it a try since our other option was a Canon 5D Mark ll.  The issue that this camera has when trying to pull a good key are the Red and Blue channels.  These channels have a tendency to be noisier than the Green channel.  Also you end with with this nice white line around the image that makes it really hard to key.  Check out my examples of these channels bellow.

Red Channel  

Blue Channel

The Canon 5D Mark Two  is a great camera and I love shooting with it.  To steal a phrase from Stu Maschwitz (his prolost blog is a must read) the 5D is an amazing Rebel camera, and it has done a lot for the VERY independent and not so independent film making community.  That being said it still has a lot of issue when shooting on Greenscreen.  the main issue is that its output is H264.  You end up with compressed footage that you have to try and get a key from.  Check out this alpha channel with a lose key pulled, you can see the compression ‘s square artifacts.  This will make pulling a key tougher, especially around the fine hair area.

Nice chunk of compression

Compression causing the hair to crunch

In this photo you can see on the back of her hair that its starting to crunch.  This is due to the compression.  There are tricks around this of course but I would obviously prefer to use a better camera.  

Quick comp with crunched hair

One way around the compression issue would be to use a Aja Ki Pro mini.  We thought this was going to be our savior for our compression issue.  It bypasses the camera’s compression and you get  a nice ProRes 422(HQ) file.  The only problem was that it didn’t seem to work with the 5D.  We could only get a 29.97 FPS and no 1080p.   Major let down when we found out that we could not use the Aja Ki Pro Mini.  

We have one greenscreen shoot left and I still need to figure out if we should use the Panasonic hpx500 or the Canon 5D Mark ll.  I keep going back and forth with this one.  

Ill see some keying results with the hpx500 and say “Lets use this one on the next shoot” then I see some keying results with the %D and say the same thing. 

We are shooting in a few weeks and I am now leaning towards the 5D.  One major reason is because the plate for the GS shoot was shot on the 5D and thats really the only reason. 

If anyone has any suggestions feel free to post some comments!

Launch NukeX from MacOS Terminal

I decided to write this simple and quick tutorial on how to Launch NukeX from the terminal since it took me a while to figure it out.  I am not very good with command-lines which is why it took my some time to figure this out. hopefully this will save you a lot of time.

Open terminal and type: sudo nano /etc/profile

(Might ask for a password)

After you type the above, a new screen will pop up that looks like this

Under # System-wide... is where I put my alias, Here is what I typed:

alias nukex="/Applications/Nuke6.0v7-32/Nuke6.0v7.app/Nuke6.0v7 --nukex"

And your terminal should look like this.

On this screen you can add as many alias as you like just change the version(Nuke6.0v6 or Nuke6.1v1).  I had one with no --nukex just to launch regular Nuke and I also have a few others for different versions of Nuke that I have on my computer.  Just remember to change the name of the alias for each version you add.  

This is a per machine bases so if you are on a network this will NOT follow your profile.  Each time you move and log on to a new machine you will have to redo this. 

Hit Control and X to quit then hit Y to save and enter.  Close the Terminal and reopen it and type it nukex (or what ever you put as the alias) and NukeX should launch.

Special thanks to the Foundry, Brian, and Tahl Niran

Basic Key - Alpha Channel

Here is a quick key I pulled in Nuke.  I used the IBK Gizmo for the edge matte and a Primatte as the Core matte.  There are still some holes that need to be filled but I'll do that later.  

I downloaded a Gizmo called the Grad that allows you to take four samples of the greenscreen and gives you back an average.  It's a lot like the IBK color but seems to work a bit better for motion blur and especially after adding a grade node to it. I got the grad node via FXPHD recommendation then downloaded it from here .

 Picture of the IBK with Grad node with Grade node and the Primatte keyer.

Here is what the Grad Node options look like

Here is the Alpha Channel that I got from the IBK Gizmo and Primatte Nodes.  (Still has holes)

Alpha Channel from Ken Fisk on Vimeo.

Basic Key - Background

Here is the Background I decided to use.  I shot this outside my work with a Canon 5D Mark 2 with the kit lens which isn't my favorite lens by any means to slow for me.

 

Basic Key

I plan on keying this very quick shot and posting a few steps along the way.  Not at all a Tutorial just a few steps here and there. The rack focus is going to be the only tricky part and I don't think that should be to tough on such a short shot anyways.  

Bike_Pedal from Ken Fisk on Vimeo.