PDA

View Full Version : reflections that show glow?


amasen
02-23-2005, 11:56 PM
I'm pretty new to maya and I'm doing a scene in which an object glows and is surrounded by some objects that have reflective properties. At the moment I can't figure out how to make the reflections show the glow... any advice? Thanks

-ash

Jozvex
02-24-2005, 01:45 AM
Unfortunately you can't, as far as I know.

The technical reason is because the glow is a post process effect applied after the image is rendered, so it's not raytrace-able.

Some people once told me that glows don't show up in reflections in real life either, but I'm not sure about that one.

Pixero
02-24-2005, 05:59 AM
I found a way to do glow based on how bright a surface is.
Just change the ramp to control the glow level and at what levels the glow shows.
Here it is in an old thread:
http://www.cgtalk.com/showpost.php?p=1438873&postcount=40

Hope this helps.

Pixero
02-25-2005, 07:44 AM
The surface luminance solution above dont work on the reflection. My mistake. :sad:

Heres another trick that DOES work to get the glow to show up in a reflection.
Im not in front of Maya so I have to do this by memory:

Create a simple scene with two spheres. Attach two materials (Blinn1 and Blinn2) with reflectivity and turn up trace depth in render globals.
Turn up the Glow on the "glowing object" (Blinn1) and position some lights to light the scene.
Create two new layers and put the object you want to see the glow reflected on on Layer1.
Duplicate the object and put it on Layer2 and also duplicate the material and attach it to the copy. Connect the Blinn3 to a Luminance node (to turn its output to a scalar value) and connect the Luminance node to a ramps V coordinate just as in my above post.
Connect the ramp to Blinn2s Glow intensity.
Hide Layer1 and render...no glow in reflection.
Now turn on Layer1 and hide Layer2 and render again...voila!! Glow in reflection.

Hope this helps.

Jan

P.S. You might have to tweak the ramp or lights to see the glow.

amasen
02-26-2005, 06:06 AM
The surface luminance solution above dont work on the reflection. My mistake. :sad:

Heres another trick that DOES work to get the glow to show up in a reflection.
Im not in front of Maya so I have to do this by memory:

Create a simple scene with two spheres. Attach two materials (Blinn1 and Blinn2) with reflectivity and turn up trace depth in render globals.
Turn up the Glow on the "glowing object" (Blinn1) and position some lights to light the scene.
Create two new layers and put the object you want to see the glow reflected on on Layer1.
Duplicate the object and put it on Layer2 and also duplicate the material and attach it to the copy. Connect the Blinn3 to a Luminance node (to turn its output to a scalar value) and connect the Luminance node to a ramps V coordinate just as in my above post.
Connect the ramp to Blinn2s Glow intensity.
Hide Layer1 and render...no glow in reflection.
Now turn on Layer1 and hide Layer2 and render again...voila!! Glow in reflection.

Hope this helps.

Jan

P.S. You might have to tweak the ramp or lights to see the glow.

Thank you for your help... however I'm unable to get it to work. I think the problem could be how I'm setting up the connections. When I connect blinn3 to the luminance node, what is my input/outputs?

Thanks

Pixero
02-26-2005, 10:16 AM
I made an example scene for you. Hope it clear things out. (Maya 6.5)

Zac256
02-26-2005, 05:34 PM
Also, it might be worthwile noting that glow is usually done in a compositing program like shake. As long as you render out in passes it's very easy to do. Not only is it easier to set up, but it gives a far, far better result than Maya's glow, and it is easier to control.

CGTalk Moderation
02-26-2006, 06:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.