I am trying to create neon lights for my assignment. How would you go about this?

… and to be more specific? where do you have a problem.

Well, I got my neon sign made with curves and sweep filters. Let's say I got a sign that says “OPEN”, how would you make the sign glow? I tried using the gvop_glow shader; but when I attached an atmosphere to my neon light geometry, it only has a circluar glow. How would I make that glow throughout my sign instead of one place?

Well, I got my neon sign made with curves and sweep filters. Let's say I got a sign that says “OPEN”, how would you make the sign glow?

I tried using the gvop_glow shader; but when I attached an atmosphere to my neon light geometry, it only has a circluar glow. How would I make that glow throughout my sign instead of one place?

to be honest… I don't see your scene and it's hard to me to imagine where is your problem, but one general remark is that glow is a last thing you want to render in 3d! Maybe there are some circumstances in which it is necesery, but in general this is a last choice! Try render your lamp separetly and add glow in post. You will have better control over hole scene and glow will look much better. You propably want to add it on your lamp in screen or Add mode, which means that you won't have a problem with alfa.

best,
symek.

I almost always do glows in compositing. One problem I run into is if I'm using Z depth files. Without Z-Depth I take the file and blur based on the alpha, mult by some ramp to get a colored glow. But does anyone know how to do a similar thing with Z-Depth info? I can't blur the Z-Depth plane because that changes the depth. Since the glow extends outside the alpha and Z-depth info, it becomes problamatic. Anyone else find a solution to this?

do you really have to use zdeph map? maybe you can rander that one object a composit it without zdeph…. I can not imagine situation in which zdeph is absolutely nessesery… it can helps form time to time, speeds up some comps, but generally you always can do your comp without zdeph.

another thing is that I cannot understand to what porpuse you use zdeph in that context. Glow is filter which influances pixels colour aroud your object. IT does not touch your zdeph…. Object can be composited, just mask it to apply glow on it only rather than on whole plate.

ok, I think I understand now, you know, you always can add your glow after you composit your object. DO you know how glow works or you just use some ready-to-use filter? Make a copy of your object before composition (without background), make it B&W, up contrast, up brightness, blur it, now add this on already composited picture with SCREEN, or ADD mode. Oh! Of course you must change colour of glow multipling it by colour of your obcejct.

If you want you can send me one frame for every layer of comp., I will try to solve it and will send you results with some remarks .


cheers,
symek.

It's like clockwork - this question comes up each and every year. Aren't schools telling their students about basic things like “don't do everything in the render”? It's not your fault, Brownies, it's just that the courses seem to be so single-minded about the approach. You don't learn anything useful for production by using the wrong tool for the job.

Obviously one of my pet peeves…

Cheers,

J.C.

ye! you see, I'm telling him that for a whole last week, but I'm afraid (maybe because of my english ) he still stands on this that he must do it in render… I don't know, I don't know….

I've never in my life done glow in 3d render… is it mean that i'm not a child?

cheers,
symek.

You guys are funny. “Rendered” glows are missrepresented in other packages. When you do a render in Maya with glow, notice how the glow is added AFTER the render goes through a first pass. The glow is a POST pass much like something that could happen in a composite given the right elements. I'm assuming “atmosphere” is just a glorified “z-depth” anyway, telling your render how much to add glow to objects based off their distance from camera and the density set in the atmosphere.

To answer your question, use Houdini like it's supposed to be used. Use the compositor to add glow to your neon light. If your teacher doesnt accept this method remind him/her that the real professionals do use these methods. If your teacher is a real professional remind him/her that some studios would rather have control over glows in the composite than have to re-render a glow in 3D everytime the director says “Can you take the glow down by .15%?”

You can hook your scene up so that when you hit “render” it will go through and render your light, put it through your comp, and give you the final result.

If you want help setting this up just ask.

I don't think it's funny. I'm not referring to other packages and their packaging of techniques in any way - I'm talking about how schools just throw an animation package at students and don't cover production tips such as this. This particular topic just comes up again and again… I understand there's a lot of material to cover and you can't address every little thing, but with all the senior competition in the workforce nowadays, and the healthy $$'s they're charging for training you, this is disappointing.

J.C.

You're right… this is a very serious matter.

http://sidefx.vislab.usyd.edu.au/houdini_video/by_topic/compositing/index.html [sidefx.vislab.usyd.edu.au]
second from bottom.

http://www.cmistudios.com/tutorials.asp [cmistudios.com]
Tutorial 18: Houdini Halo Image Based Glow

Thanks…I forgot about that tutorial. I've watched it and its pretty good.

But my new problem is…if I'm doing an animation and I want that glow to be moving, how would I go about it?

I still haven't solved my previous problem…the one with animated glow.

So far, I've made myself the glow (from the tutorial). But I notice that the glow is only for a still picture. If I wanted a glow that moves with my character, how would I do that?

I'm thinking about having two different renders. One with only the glowing object rendered and the other with the normal animated render. And then I was thinking in compositing the two together; with the glow that I've just created attached to the glowing object.

But I can't find a way to render just the alpha for my glowing object. I tried to play around with “deep raster” only with a still image but it doesn't seem to work. I've selected an image from the File/Plane Name but it still doesn't work.

Help…

Brownies

it still seems that youre trying to do the glow in a 3d render. whether you render two different passes: one of the object, one of the glow, you are still trying to create a glow in 3d which will just be much better controlled in 2d in your compositing app. i know the tuts were based on single images, but if you were to render out an image sequence of a pass of just your object with an alpha and nothing else, then you will have that sequence to apply the glow to and manipulate however in comp, not just a single image.

i still suggest trying to do this in a 2d composite, but if you're really wanting to experiment with trying to do this in 3d, then you might have some luck with pushing caustics to create a 3d based glow. i did this a while back for an intro animation I did and was pretty happy with the results. but like said above here and many other places, i had extremely limited control after the render and I spent some time on messing with settings till I got the look and feel I wanted.

here's a link to the clip if you are interested (it's quicktime, just click on the “click to play” image and choose either ‘intro animation’ or ‘outro animation’:

http://www.nocturnal-illusions.com/bulb.html [nocturnal-illusions.com]

hth,
dave