View Full Version : Need Help with Glow and Luminosity

01-03-2004, 05:16 PM
Hey all,

I am working on a titling sequence. I have these "neon" tube letters, and I have put glow and luminosity on. I am mostly happy with the look, but they don't seem to be giving off any light / glow on the floor / back wall.

Do I need to turn something on for this to happen?

How do I get them to emmitt light that hits other objects, but still in the form/shape that they are in.

Any suggestions would be most welcome.

Thanks in advance.

01-03-2004, 05:34 PM
I guess turning radiosity on might work, but I am looking for a way to do this without increasing my render time 10x over.


01-03-2004, 07:06 PM
You need to turn Glow on in a second panel, I forget which one. I think it's under the Scene Tab, near Corona??. It's just a small check box on one of the panels. Sorry, I'm at the tail end of a 12 hour render, can't check it right now.

01-03-2004, 09:21 PM
Thx, its actually turned on there as well. You can see the glow in the picture.

However I did solve the problem tonight. Woo hoo!

I put a linear light with each letter, and coloured it appropriately. I got the effect that I was looking for, without having to use radiosity.

Saved me about 30 hours of rendering time. Thank goodness.

Check out the results.

01-04-2004, 02:31 AM
I had the same problem with letters, but I turned the side (of the letters) into lights.
I could turn the Letter faces back down to a regular color and no glow (which covered everything) and I needed to see the letter faces.
I ended up with this:

I did have a desk there but took it out as the render time for a totally glass desk got up to 58 hours per frame:mad:
Now at 18 min:D
So a wood desk will go in.
Oh yea, lights in ceiling are polylights too
Yea..I gotta get rid of some reflections:cool:

This is background for a bluescreened talent in documentary
The glow I first used even covered the cables holding the plasma screen, whereas a lighted poly only lights around the poly and I can now see the cable.

01-04-2004, 07:03 AM
Am I missing something here?(sounds great)

01-04-2004, 07:53 AM

Ok I am intrigued. You said you turned the side of the letters into lights.


I used linear lights, but couldn't figure out how to change the shape of the line. It looks like your letters are lit around the perimeter.

Do tell . . . . How?


01-04-2004, 08:34 AM
Luxigons of course;)

Couldn't think of the right word when I was replying so just said Poly lights which is what they do.

Just did a search here and came up with 3 links if I remember.
was awhile back.

Then I extruded the letters as usual

BUT then I took the Knife tool and made a cut in an edge view so as to make a very small stripe of polys at the back edges of the sides of the letters.( the light eminates from the center of a poly so I wanted the lighting close to the wall and not close to the letter faces) (But you can set where you want)
Highlighted them and made them into Luxigons

In layout do a convert luxigons (as area lights I think I used,but you have a choice of any light). open the multi-lite button (free on flay) left click on first Lux light, shift click on last Lux lite and do a color, then intensity ( I used 15%) then render.
Play with the settings so you get what you want.
I tried the volumetrics on point lights once and could add any of the settings in the preset files and made for some strange lighting sets but it wasn't what I was looking for. (you know like 'boiling sun, rocket engine (and these looked cool to see little jets of flame coming out the sides of the letters, but I didn't want to burn down the walls.:D

I'd have to open the scene up again,but got something else rendering, but I think I had something like 300 lights for the green and 500 for the Blue letters. Not absolutly sure.

But you can set all individually as all kinds of lights so if you have certain areas that need different lighting then just change the lights in that area. (like points changing over to spots for part of the edge and then back to points) But that may take awhile as you have to find a light in the poly area and work from there.
Haven't figured out how to specify different Luxigons in modeler yet.

01-04-2004, 09:07 AM
Oh yea, almost fergot..
different Font types will give you different amounts of side polys when extruded, so if you need more lighting on the sides (like the Letter 'T' above) where only 1 poly is made then you have to knife some extra polys to make those extra lights.
Remember the light eminates from the CENTER of each poly that is lit.

Don't need so many lights then don't highlight ALL the polys
(Maby every second or even 4th on the tight curves where many polys are made)

But you would have to play to get what you want.

01-04-2004, 10:27 AM
better example to show what I mean.
size is 10 foot polys.
16 sided disk, bandsawed to make groove.
center stripe of polys made into Luxigons

Globally set to red lights but went in and seperately changed the green, blue and yellow.

Can't see good in single frame but Blue light is set to the Blue lightning looking preset and looks really cool when rendered to animation.

Now if you need something like this complete unit (lighted parts) then you COULD COPY the polys you want to be Luxigons to a new layer, change them to Luxigons and save object
In layout you can now animate the Lux layer so that it rotates in the object.
Flying Saucer Edge:D
Makes good Star Trek type engine nacells light strip or groove

Just remember the closer your camera gets the more detailed the lights, so you'd need more lights.(in newsroom example, if camera went next to the letters, the individual lights would start showing, but as that shot is as close as it will get then it looks ok as it is)
so in above saucer example I would subdivide a few times, delete all the polys that I dont want lights and leave 1 strip of polys then Create lux polys.
It would create more lights, BUT you could get closer to ship without seeing individual lights.

Hope I explained it all well.
I don't do tuts well.

01-04-2004, 11:18 AM
Wow, thanks. Thats a lot to digest. Thanks for the info.

CMP 2003
01-05-2004, 11:40 AM
WOW, thanks for the info to the outside reader, luxigons are great, cant wait to use them

01-05-2004, 12:50 PM
OK ColonelBob
What did you do to yours??
We wanna see!!!

01-05-2004, 01:24 PM
If you are using radiosity anyway (which we all like to avoid if we can) you can use "roughed out" versions of your letters in the for of simple double sided surface quads. You then hide these in the object that has glow enabled and luminosity turned up. The neon lights themselves have their "unseen by rays" check box checked as they don't need radiosity- only the "glowing plolys do".

So your letter "S" would have four quads in it that have a high lumiosity setting. The letter T would have two quads etc etc.

The advantage in using this method is that LW has to only calculate a few Lumi- polys instead of hundreds.

I hope this makes sense- I've used it go get some good effects when combined with "glow". I'm fairly sure too that you can use Two point polly chains, but don't quote me on that.

01-05-2004, 04:29 PM
- open photoshop (or your preferred 2d app)
- build a simple white background
- new layer
- colored script like that you have modeled
- blur a lot this layer
-save it and use with spot light, like proiection image.
this light must be on only for background and ever obj which can be reached from letter light.

01-05-2004, 05:02 PM
Thanks everyone for all the help.

I am not using radiosity. The image is just a frame from a 75 second animation that I am working up, and I can't give the render time to it.

Thank you all for the great suggestions. I think I have the look I want (temporarily) with the linear lights (check the two images I have included in the above posts).

I will probably come back to this in the coming months but I have so much to do and so little time, that I gotta crank it out.

I am a Grade 5 teacher and we are making a sci-fi movie with the kids. So I am working on spaceships, titles, space scenes etc. LOL I am sure I will be back for more help as the time goes.

Thanks again for all the suggestions and help. This message board is full of awesome helpers.