Maya 2020 fundamentals - modelling the real world
Get halfway through a model and find it's an unworkable mess? Can't add edge loops where you need them? Can't subdivide a mesh properly? If any of this sounds familiar check this course out.
# 1 17-12-2012 , 01:44 PM
Subscriber
Join Date: Dec 2012
Posts: 4

Rendering Light Bulb Glow

Hello,

I am new here and also have only been using Maya for around 2 months, so please go easy on me! I have followed several tutorials and decided I would have a go at creating something from scratch with no video tutorials etc to guide me.

I tried to create a realistic light bulb. But it doesn't quite look right.
I can't replicate the glow! And the glass looks smudgy?

The first pic is the full light bulb, which looks ok, a little dark maybe.
But the second one is smudgy, the glow of the filament is non existent, I want it to actually shine a little light around the scene, not too much, just to give the idea it is a bulb.

I have used mia material X for the filament and glass, and for the filament used the 'Advanced>additional colour' option to add a mia_light_surface. If i turn the intensity up on this the filament just goes white, if I turn the Fg Contrib up, the filament goes more yellow. There is no glow really on the scene?

Any one know why or can give me a better way to achieve this?

Thanks again!

Justin


Incase the attachments don't work>>
user added image
user added image

Attached Thumbnails
# 2 17-12-2012 , 04:15 PM
NextDesign's Avatar
Technical Director
Join Date: Feb 2004
Posts: 2,988
You should really do things like glow in post with Photoshop. Not only will it be faster, but it will give you more control as well.


Imagination is more important than knowledge.
# 3 17-12-2012 , 04:34 PM
Subscriber
Join Date: Dec 2012
Posts: 4
Thanks for the response, I really wanted a way to achieve it in Maya just so I could animate if needed, Using this as a learning tool! Any ideas on how it can be done with mental ray/lights etc?

# 4 17-12-2012 , 05:37 PM
Gen's Avatar
Super Moderator
Join Date: Dec 2006
Location: South FL
Posts: 3,522
You could assign a surface shader to the object and pipe the 'result' of the mia into the out color of the surface shader using the connection editor and control the glow from that shader. However, doing it in post will indeed give you more control, and it can be animated from there, just get your image sequences to a compositing package like After Effects, Nuke etc.


- Genny
__________________
::|| My CG Blog ||::
::|| My Maya FAQ ||::
# 5 17-12-2012 , 06:09 PM
NextDesign's Avatar
Technical Director
Join Date: Feb 2004
Posts: 2,988
Glow is also caused by a number of optical phenomena. One of them is particles in the air. You can create these in mentalray by using the parti_volume shader.

Another few things you can play with:

1) Put a physical lens shader on your camera, which will help "blow out" areas correctly.
2) Attach an mib_blackbody shader to the additional color attribute of the filament's additional color. This will allow you to specify a physical color temperature for an incandescent bulb. (Usually around 3300K) You'll need to push the intensity to some stupid number (something like 1000000) in order to see it properly.


Imagination is more important than knowledge.
# 6 17-12-2012 , 06:35 PM
Subscriber
Join Date: Dec 2012
Posts: 4
Thank you both,

I will try each of your options just to see the differences really! The lens shader is for creating a depth of field isn't it? Unless I am referring to the wrong one. Well I will have a play and see what I can come up with! I tried one on a previous tutorial but I couldn't get it to focus correctly, it just blurred out the entire image... So i resorted to photoshop. Being a graphic designer by trade I feel more comfortable with that! Just wanted to learn a new skill!

I will be back with my results, either with a 'yay it's worked' or 'nay, i've hit another brick wall'!

Thanks again

# 7 18-12-2012 , 01:32 AM
NextDesign's Avatar
Technical Director
Join Date: Feb 2004
Posts: 2,988
The lens shader does a bunch of other things besides depth of field. It also simulates a real camera; so you have exposure, aperture, ISO, etc.


Imagination is more important than knowledge.
# 8 18-12-2012 , 04:00 PM
Sircharles's Avatar
Registered User
Join Date: Dec 2010
Location: Uk
Posts: 193
Have never used the mib_blackbody before, so did a quick render with one at 3300K and intensity 10. I had not used a lens shader either and I think it adds nice realism.

Thanks NextDesign.

Attached Thumbnails
# 9 18-12-2012 , 05:45 PM
NextDesign's Avatar
Technical Director
Join Date: Feb 2004
Posts: 2,988
No problem Charles. mentalray is full of these neat little features, but they aren't documented that well, so it's difficult to know how to connect things properly.

Another interesting thing you can do is with a light, go to it's attributes, and under the mentalray light shader, map a "physical light". In the color, you can use a black body as well. It can make some nice effects as well.


Imagination is more important than knowledge.
# 10 18-12-2012 , 07:02 PM
Sircharles's Avatar
Registered User
Join Date: Dec 2010
Location: Uk
Posts: 193
Oh yes - I remember hearing about that - but it went over my head at the time.

I think that might work nice for a lamp and a light bulb, maybe add some volumetric fog as well would create a nice scene. Was meaning to try that at some stage.

Problem is all these things are nice for stills I'm guessing, prob expensive for animations?

# 11 18-12-2012 , 07:37 PM
Subscriber
Join Date: Dec 2012
Posts: 4
This looks good, I am currently trying a render but have had to turn the final gather up as the light is being blotchy, is taking forever to render, might be using the wrong settings but here goes nothing!

It's a shame about all the circles that are appearing everywhere, will look for a solution on that, but either way is closer to what i was aiming for.

Thanks guys!

Attached Thumbnails

Last edited by jbyrne; 18-12-2012 at 07:45 PM.
# 12 19-12-2012 , 02:58 AM
NextDesign's Avatar
Technical Director
Join Date: Feb 2004
Posts: 2,988
Looks good. To speed it up, try the following:

In final gather, turn down the accuracy to around 50. Turn down the point density (Eg 0.5), then increase the point interpolation (Eg 20).


Imagination is more important than knowledge.
Posting Rules Forum Rules
You may not post new threads | You may not post replies | You may not post attachments | You may not edit your posts | BB code is On | Smilies are On | [IMG] code is On | HTML code is Off

Similar Threads