Adding glow

I do have basic understanding of the node editor, but I don’t seem to be able to achieve what I want:

I have a spaceship with engines. I want the engines to give off some glow. My setup:

  • Spaceship + Engines in layer 1 with lamps (for the original picture)
  • 2nd pair of engines in layer 2. without lamps, so that you only see the halo.

I want to render this second pair of engines (know how to do this), and then:

  • Make everything which is black (the engines itself) transparant, so that you only have the light ‘in’ the engines left (don’t know how to do this)
  • Enlargen & blur this light (I know how to do this)
  • Make this ‘glow’ very transparent, that you can just see it (don’t know how to do this)
  • Place the glow over the original picture (I think I know how to do this)

Could anyone help me? Thanks! (Pointing out a tutorial is ok as well :wink: )

A different approach would be to assign a Pass Index to the engine objects in the Objects and Links panel of the Object buttons. Make sure to enable the Index pass in the RenderLayers panel. Then you pipe that Index pass through an ID Mask node, which can be found under converters. Set the ID in this node to match the Pass Index you set for the engines, and the node will output an Alpha channel that is just the engine objects!

You don’t have to mess around with duplicating objects and fooling with materials.

From there, I would make a blurred version of the mask, invert it, then subtract the original mask from it (this will give you a blurred area around the engine, but with the engine itself knocked out of it).

You can use that final mask as the Factor for an RGB curves node set to brighten, or however you had decided to “glow” things.

That sounds pretty easy ^^ Thanks for the tip, I’ll try it!

Bumped into some problems :slight_smile:
I tried both ways of subtracting (original minus new, new minus original, although I don’t know which one is which one :D), but I don’t get the blurred are with the engine knocked out, as you describe it.

With your method, I will get the engines glowing, but to be honest (sorry for my lack of clarity) I wanted to make the yellow stuff insíde the engines glow. I did these with halo’s, which don’t seem to work with an index pass… Or am I missing something?

Thanks!

Edit: First image, top mask is the original mask, the 2nd & 3rd are the substractions.
Second image: The ship. I hope this makes clear what I want to glow.

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I’m afraid I’m giving up on this one. I did achieve something, but that made the rendertime much longer. I’ll stay with the way it is right now.

Thanks for the help though, I’m sure it’ll come in handy next time!

Sorry for getting to you on this so late.
Here’s my advice, don’t put them on two diferent layers, just one.
You have to seperate the part of you enginve that you want to “glow” as a seperate object, not the engive it’s self, but the part that you want to emit the glow (in this case your yellow part).
Set the ID idex to 1 or 2(every object created is automatically set to 0).
In the node ditor, do as harkyman said, but the one thing he left out is that you will have to combine your output from your ID index with you original rendered image.
The way you do this is you add a Color Mix node and pipe your rendered image and your ID index output to this, it will mix the two, the setting that you probably want to give it is Screen, or Add, Mix doesn’t really help it much.
It will look dark when you do this, but turn up the factor to 1.00.

Hope that helps, if you want i can create a mini tutorial if you don’t understand.

-Jimmy

Any .blend? We could see what we could do…

I’ll see what I can do ^^

http://uploader.polorix.net//files/1492/DaedalusBA.blend

Here it is. I hope you can see what you’re doing now :wink:

If you decide to use it for something else as well:
Please notify & credit me when you use the model, no commercial work allowed.