chromatic aberration

-

chromatic aberration

 Most people doesn’t understand What is "chromatic aberration"and struggle to handle it on post production. Here is simple solution to understand and produce good result in post.

First is first..

What is chromatic aberration?

Chromatic Aberration, also known as “color fringing” or “purple fringing”, is a common optical problem that occurs when a lens is either unable to bring all wavelengths of color to the same focal plane, and/or when wavelengths of color are focused at different positions in the focal plane.


Look below image Right side. You can see the red color (fringing) bleeds on the object edges.Its because of chromatic aberration.


 How its happen?

Chromatic aberration is caused by lens dispersion, with different colors of light travelling at different speeds while passing through a lens. As a result, the image can look blurred or noticeable colored edges (red, green, blue, yellow, purple, magenta) can appear around objects, especially in high-contrast situations.


 Types of aberrations.

1. longitudinal chromatic aberration 2. Transverse chromatic aberration



 How to mimic this effect in Nuke?

Create chromatic aberration in Nuke is really simple one. "Transform" "TransformMasked" and "Lens distortion" nodes will help you to create chromatic aberration effect.
(Some gizmos are available in internet)


 

Transform node will create aberration effect to entire image. See blow example image.
(Here i used scale knob on Transform node to create aberration)

Before and After result:


Using "TransformMasked" tool will allow you to create aberration in specified place on the image.


Result:


How to convert this process as a custom "gizmo" in nuke.

step-1. select all nodes expect input and roto nodes. Go to-->Other-->Group and click. Keyboard short-cut "alt+g".

step-2. Once make the group go to "Group1 Node Graph" and give the name to inputs and connect the output to last node.



step-3. Go to node graph and start to add custom knobs by selecting "manage user knob".



step-4. After add custom knobs start to connect the knobs via expression.

           " aberration channel checkbox" to "Transform" nodes disable knob.
             expression - (parent.red)-1

           " aberration_value " to "Transform" nodes "translate.x" knob.
             expression - parent.aberration_value
(Here i used X Translation to create aberration, You can use scale Instead of x)

step-5. Export the "Group" as a gizmo.


Add this gizmo in to your nuke plug-in path and enjoy.





Comments

Post a Comment

Popular posts from this blog

Export Nuke's retime information

-
Image
Export Nuke's retime information To 3D packages: This is happen while working with production. In most cases retiming is done beforehand or at the end of a comp. Some time shots getting retimed after Match-move is done. By that time Nuke's retime data (curve) will help to match the tracked camera to new retimed plate. Here is the trick to export nuke's retime date (curve) to 3D packages such as maya, max, Houdini etc. Here im explaining how to export nuke's retime curve to maya. Constant re-speed. I want to retime my input by 200%. Add a retime node and change the speed to 2. Don't forget to change the filter option to None . Retime node doesn't generate retime curve at all. So note down the output range. It changed from original range 1001 - 1042 to 1001 - 1021. Which means our input ended with 1021. Add a TimeWarp node and set keyFrames based on our retime output result. Set a key frame at 1001 as 1001 in input frame knob. Got
Read more

Lock and unLock node settings in nuke

-
Image
Lock and unLock node knobs Nuke doesn't have inbuilt function for lock the node settings( knobs, sliders), Like fusion's node lock function. While working with bigger scripts most of the time we accidentally  adjust the node sliders with out knowing which node is selected. ( what the hell is happening i didn't adjust anything..... ????!!!!! ) This code lock selected nodes knobs. So no worrier’s about accident changes. Right click on the nodes property panel. You will get knobLock & unlock short-cut key. menu.py: import lockNode nuke.menu("Properties").addCommand('lock_Knobs', 'lockNode.lockNode(True)') nuke.menu("Properties").addCommand('unlock_Knobs', 'lockNode.lockNode(False)') Download:  locknode.py Hope this will help you friends.
Read more

Working with UV pass inside NUKE

-
Image
Working with UV pass inside NUKE UV pass will allow you to re-texture surfaces and add some elements ( like text, batches, picture frame ) later in the compositing stage. Here i place my name on the surface and apply motion blur inside nuke. Creating UV pass inside MAYA: Maya 2012 have inbuilt UV render pass. Open up render settings under Passes tab select create render passes and choose UVpass and add. Maya->Render Settings->Passes->UVpass If you want to create custom UV pass Follow below link. http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=13481445&linkID=9242258 Enable float values for rendering For render UV pass from MAYA you must change your colour bit depth from the standard RGBA 4x8Bits per channel to RGBA (Float) 4x32 Bit (full float). Open up your 'Render Settings' and at the bottom of the 'Quality' tab change the 'Date Type' to 'RGBA (Float) 4x32 Bit. choosing File format f
Read more