2D Volumetric rays
Here i'm going to explain Creating 2D Volumetric rays in nuke.
As a compositor and 3D artist every one really love Volumetric rays. Creating Volumetric rays in 3D packages such as Maya, 3dMax and any other 3D software’s are quit expensive. Its took long time to render for producing nice Volumetric rays.
Creating 2D Volumetric rays doesn’t look nice like rendered in 3D packages. But we can save some valuable times by create this effect in 2D.
You can create nice Volumetric rays effect like above image in Nuke. I used "Godrays" "Noise" and "roto" nodes to produce above result.
Here we go............
Step-1. Import image into nuke.
Step-2. Draw a roto shape to the light. If you have matte (alpha) will use that
instead off roto.
Step-3. Add "GodRays" node and connect it to "roto" node. Move the center point
to the opposite direction off rays direction. Here i placed the center
point to the left upper side of the image.
Step-4. Change the "GodRays" scale value. I set 4.5 as scale value.
GodRays default scale value is 1. ( change as per your need )
This will give you blow result:
Step-5. Change the "steps" knob value to 8 will give you the below nice and
Step-6. Composite this result with input.
It looks nice. But.... hold on a second. I like to fade off my rays when its reaches the ground. How to do that.
Here is the solution.
Step-7. Again go to GodRays and adjust the "knob" called 'to color'.
Reduced 'to color' knob value will give below result:
Now its look really nice and fallen off. But its not the final result, you showed first??.
How to create the breakups on the rays. Means lights breaking through some objects. In 3D packages will add some objects for light cut through that. But how to mimic that effect in 2D.
Its really simple one. Artistic approach will help us to mimic this effect.
Step-8. Create a 'Noise' node and multiply it with the "roto" node.
This will give you the below final result:
Adjust the noise value as per your need.
You can change the rays color by adjusting color value of 'from color' and 'to color' knob on GodRays node.
Multiple roto shapes will produce some nice Volumetric rays.
One more example:
Hope this will help you guys.
Nuke file: https://skydrive.live.com/redir?resid=776F8351D9892B6A!270