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CyanSeaHorse

Neon sign

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Hey all,

 

I'm a bit stuck and I was hoping I could get some advice here.

 

I'm branding a TV show and was tasked to design a Neon sign in c4d. We're getting the sign made to use on set for the tv show, however I need to make the titles using the 3D model.

 

I came across this awesome break down which, although is quite in depth - it's not step-by-step enough for me to apply to our concept. The problem I have is when it comes to rendering multiple passes to control the illumination in AE.

 

So instead of going that route I decided to try light the scene in C4D using the illumination channel on the material. It looks nice in a still frame render but as soon as theres multiple frames then theres way too much flicker going on. Below are 2 renders, one with the illumination enabled and one with just the lights enabled.

 

My question is : How can I either get rid of the flicker that occurs due to the GI, or how can I render out a pass whereby I can adjust the illumination of the neon in AE? I understand Travis used the neon in a separate pass as a track matte, but thats about as far as my knowledge can divulge.

 

Any help or advice is greatly appreciated!

Thanks

 

 

woBEcLP.jpg

 

GLmJJFC.jpg

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I realize that you're asking a specific technical question, but it occurs to me that you might get more bang for your photorealism buck by looking at standard neon sign setups to understand the logic behind how they're built.

 

For instance, there are no sharp corners in neon signs because they're made of hollow glass tubes that are manually bent while hot and pliable. You can make a neon sign other ways, but 99.9% of the time, it's bent glass tubes, which are pretty much a standard thickness because there's electrically-reactive gas inside and yadda yadda.

 

Also, the way they're constructed is usually of as few tubes as possible, meaning that one tube will typically be formed to create several letters or shapes, and to make it look like those letters/shapes are disconnected, the part of the tube that's not meant to be seen to glow will be painted opaque. Then there's an electrical input at the start and end of each tube, and each individual tube is held in place by clasps or glass rods that extend back to the surface it's to be hung on. You can kind of see here how it typically works...

Neon-Letters.jpg14dcc0472a39f911f0b1f4d82b2ce99c.jpg

 

There are certain embellishments that work with neon, like metal backings, and so forth, but the process of molding a frame or cutting a backing is necessarily different than of bending glass, so the shapes never really match perfectly, and as a result, they're usually offset from each other so the imperfections are less apparent.

 

The point of all of this is that if you're trying to make an image that conveys "neon sign" to your audience, you're going to get a lot more mileage for your efforts if you build it like a neon sign, before you start worrying about whether your global illumination settings are on point. That's kind of missing the forest for the trees, y'know?

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Thanks for the in-depth reply, however I'm not exactly after something that is hyper-realistic. I just want the light inside the tube to illuminate the wall without flickering.

 

The type of neon sign that I'm building does not necessarily have to be like the glass-tube neon signs, it could resemble that of something made with Neon-flex. It would be great if I could control the illumination in after effects using an object buffer from 4D, as Travis had done in his breakdown video. I just don't understand how the object buffer works and how he managed to use that in AE.

 

Thanks again, I wish I had the time to build the neon tube and get the materials right, as if the tube looks sandblasted when it's not "on"

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Totally. Artistic license being what it is, that's totally valid. It just seems like you're fighting an uphill battle here already because you're trying to convince the audience of something. Namely that there's this sign on a brick wall. And you're going as far as to show that it has power cords because it needs power, and it's mounted on a scaffold stuck to the wall because gravity is real, and it needs these fasteners to hold it here and here, and so forth. You're already making a plea to the audience to look at it as a real object. You're asking them to scrutinize it as such. And if you're going to take that tack, it seems like the best usage of your effort is to keep taking that tack.

 

And yeah, when it comes to the actual lighting, you're on the right track with the object buffer. You can read about how it works by doing a search, and when you get it set up, you'll be able to save a simple b/w matte in the shape of your neon parts, and you can take that into AE and use it as a luma matte to create layers in that same shape that you can colorize and glow and whatever else for your lighting effect.

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I just don't understand how the object buffer works and how he managed to use that in AE.

 

 

Look for a tutorial on track mattes or alpha / luma mattes. Thats all an object buffer is. There are tons of tuts out there.

 

If you're going to be adding glows and such, it's helpful to pre comp the rgba/beautypass with the luma matte, and do you're track matte in there. Then put the glow on the pre comp. That way the luma matte won't also be cutting off all your cool glow-y stuff.

 

 

Theres also this.

 

http://greyscalegorilla.com/blog/tutorials/how-to-use-textures-and-objects-to-light-your-scene-with-and-without-global-illumination-in-cinema-4d/

 

It might help you get around the GI flicker and get you closer to the look you're going for without track mattes/object buffers

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Thanks for the advice guys, I'll be looking into track mattes etc using an object buffer.

 

I tried turning off GI, and putting in a light just to try replace the illuminated material, and it still took an age to even try render. Is there a way to speed up renders by optimising polygons or something like that? Sorry for the noobness

 

For now i'm trying to just do a render pass with the neon enabled and GI, and then I thought to do another render without GI, neon off, lights on. But my render times are very strange,

First frame was 1:40, second frame 35mins!

 

dd2tYp8.png

 

TyTYhhm.png

 

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tsX6TKb.png

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The GI minefield.

 

How many polys has your scene got? Optimisation could really help.

 

QMC will help stop the flicker in the render. I wouldn't put samples on low, you could end up with a very noisy image. Medium minimum. Make sure Auto Save and Auto Load cache are enabled.

 

Any reason your antialiasing is off?

 

Look at using a renderfarm such as Rebus if you're nearing your deadline and panicing.

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How many polys has your scene got? Optimisation could really help.

 

Probably too many, how do I check?

 

 

 

QMC will help stop the flicker in the render. I wouldn't put samples on low, you could end up with a very noisy image. Medium minimum. Make sure Auto Save and Auto Load cache are enabled.

 

QMC is really slow though, too slow to preview even. Auto Save and Auto load are enabled

 

 

 

Any reason your antialiasing is off?

 

I was trying to speed up the render

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Post a pic of your wireframes.

Is that brick wall just a texture? No bump/displacement.

Is it possible for you to post the c4d file? (granted you're not overstepping an NDA or something)

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Even if i turn that layer off (the green tick?) - it still takes forever. Is it better to control this illumination somehow in post? Or do I need to render it out in c4d. The flicker from the GI is terrible, and I can't even render a few frames to see if i've fixed it

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Even if i turn that layer off (the green tick?) - it still takes forever. Is it better to control this illumination somehow in post? Or do I need to render it out in c4d. The flicker from the GI is terrible, and I can't even render a few frames to see if i've fixed it

 

Sounds like you need to do a bit of debugging on that scene. Save a test version and try a render with simple white diffuse materials on everything. If you've got your lighting right, that should be fairly quick, and flicker free. You're aiming for a balanced look, no crunchy black shadows, no massively overbright white areas. Simplify as much as you can to make the test scene quick, then add details back in to look for culprits. The sweep for the 'hub' lettering looks way too dense, change the 'intermediate points' setting for the swept spline to 20° or so.

 

If it's not working (GI and animation using C4D's renderer aren't my best friends) - don't fight it - try a solution using area lights instead.

 

If you're in the mood, and tied to GI, the C4D help is really, really detailed in the GI sections. Specific to your case:

 

  • When using IR+IR/IR+QMC: if flickering occurs on surfaces, the Samples value probably too low (four-digit figures may even be required). If, on the other hand, flickering occurs in small regions around an object, the Record Density value is too low. In this case, decreasing the Maximum Spacing value should help. If this does not do the trick, set the Record Density to a higher setting.
  • Flickering can even occur at optimized IR+LM settings if the base light map is of poor quality (see ,Optimize Light Mapping’ below).
  • QMC+QMC will not flicker (the render times will increase accordingly; these will be at a maximum).

 

If the scene becomes quick with simple white diffuse material then look at the materials in the scene - some glass/metal presets I've seen knocking around have high values suited to ultra high-quality stills, but totally unsuited to animation.

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Why even bother? Sorry, but so far every single post on this tread has missed the obvious: Don't use GI?! You know, there's this thing callled the Proximal Shader and MoGraph Cloners can do wonderful things with lights... 'nuff said.

 

Mylenium

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Why even bother? Sorry, but so far every single post on this tread has missed the obvious: Don't use GI?! You know, there's this thing callled the Proximal Shader and MoGraph Cloners can do wonderful things with lights... 'nuff said.

 

Mylenium

 

To be fair, Ianfreeze explicitly linked to a video showing geo-lighting without GI, and I suggested not using GI. So not quite.

 

Mr SeaHorse - assuming you get a setup you like the look of, I did some neon brightness capture a while back, if you want some real-life flicker curves, file is in this thread:

 

http://mograph.net/board/index.php?showtopic=29928

 

Easy enough to fake doing your own curves - but not always as convincing.

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Thanks for all of the replies and advice guys, I think I'll go with the GI off option unfortunately. ChrisC Thanks for the flickr file, it works nicely!

 

With the GI off option, is there any way to get light to illuminate from the hub text? I've managed to place some lights behind it which work nicely with the brick - however no light shines out the front. Does the "luminance" option in the material editor become redundant when GI is off?

 

I understand how to render out a luma matte with object buffer so I guess I could try adding a glow to that and blending it in AE.

 

Regardless, thanks for the helpful discussion!

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Thanks for all of the replies and advice guys, I think I'll go with the GI off option unfortunately. ChrisC Thanks for the flickr file, it works nicely!

 

With the GI off option, is there any way to get light to illuminate from the hub text? I've managed to place some lights behind it which work nicely with the brick - however no light shines out the front. Does the "luminance" option in the material editor become redundant when GI is off?

 

I understand how to render out a luma matte with object buffer so I guess I could try adding a glow to that and blending it in AE.

 

Regardless, thanks for the helpful discussion!

 

As Mylenium alluded, Mograph is going to be your friend if you're going the non GI route. Material luminance doesn't cast any light into the scene when GI is off, so you have to replicate this effect using regular lights. By placing a light into a Mograph cloner set to Object mode, with your neon objects as the reference object, you can place lights on the surface of your neon geometry which will create the lightning effect. You may want to set the project options for the light to exclude the neon geometry to avoid the light being blocked by the geometry and having to deal with weird shadow issues, etc.

 

This is likely more than you're going to want to get into right now, but a while back I created an Xpresso setup to create strobing, pulsing and flickering lights (the setup also works on virtually any other parameter in Cinema). This setup came from a project where I had to create a bunch of neon signs; so I figured I'd pass it along in case you might find it useful (link below.)

 

Strobe, Pulse and Flicker

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Thanks for the advice Scott Frizzle! This solution seems legit, i've tried it so far and from what I can see it has the potential to work but I have a few problems at the moment.

 

The lights seems to occupy a large space although I haven't been able to get a single frame render out yet because it seems to take way too long and bogs my computer down (I'm working in AE simultaneously on other projects and need some memory to meet my deadlines).

 

From what I can see from the little bits it has rendered it looks like the lights are way too bright. I toned down the light's brightness in the cloner to 1%, and changed the cloner's "weight" setting down to super low but it still looks like it's trying to render too much light which is slowing everything down. Is there a way to bring the light's intensity right down?

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I probably should have been more detailed in my description as there are some things that can go wrong. I've included a simple scene file that illustrates most of this at the link below. Here are some things to check:

 

Your geometry is fairly high resolution so depending on the distribution settings in the Cloner, you may be creating way too many lights. I assume your neon objects are Extrude Nurbs or editable geometry? Try using the Surface or Volume distribution settings in the Cloner and experiment with the Count to get a good balance of render time vs realistic lighting. The distribution of lights will not be perfectly uniform but I doubt it will matter.

 

Make sure the light you are cloning has falloff enabled in the Details tab. Otherwise you are casting infinite light from all your cloned lights which of course will over light the scene. I'd use the linear falloff setting which will be more controllable for this purpose.

 

If you have shadows enabled for your cloned lights (which I imagine you want) try using soft shadows at the default setting. Using area shadows is going to murder your render time with so many lights in the scene. Again, be sure to set the Project settings of the cloned light to exclude your neon geometry.

 

Neon light scene file

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This is working extremely well so far, thanks for the in depth reply! I doubt I will get it nearly as amazing as Travis Laidlaw his in his breakdown but considering the time that I have this solution is perfect. Can't thank you enough man, I owe you a beer (or a few!)

Edited by CyanSeaHorse

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