transparent material to take on light color

mattjgerard · March 14, 2018, 08:11:46 AM

I've searched for how to accomplish this, but how can I get a transparent material (glass, solid glass, gem, etc) to take on and transmit the color generated by an area or point light? I have a tower light for machine indication that has colored LED's behind transparent plastic. In the actual unit itself, the plastic takes on a cast of the color of the LED's.

I can get this to work slightly by coloring the glass color, or the transmission spec color, but I'm hoping to create or find a material that will derive this from the light in the scene. I've tried turning on caustics, which seems to help a little, but just not as intense as I'm seeing happen in the actual tower light. I know theoretically clear glass won't be colored by transmitted light, but in reality it is, I can see it right here on my desk demo. Its almost a fresnel effect.

I know I can get the effect in PS, but would like to mock up as much as I can in KS so I can share materials and techniques with the other artist I work with. Am I looking at doing small tiny noise and imperfections in some channel of the material to catch light and refract? The material is a polycarbonate clear plastic about 4 mm thick. The last file is one that was rendered 2 years ago in a different render engine. Trying to duplicate.

INNEO_MWo · March 15, 2018, 03:39:07 AM

How about this materials?

bdesign · March 26, 2018, 05:54:15 AM

Hey Matt-

I modeled a basic mock-up of your device, and here is what I came up with. First image is after post processing in Photoshop, second and third images are raw renders with LED lights on and off. The key to getting the clear plastic to take on the light color is to enable Diffuse Transmission (15% grayscale in my example). The diode lights are small spheres (two sets), to allow independent control of the illumination (Point Light Diffuse) and appearance (Emissive). 24 Ray Bounces, Caustics enabled, no GI. KSP attached.

Here are the material specs:

• Clear Plastic (Polycarbonate):
Advanced material, Diffuse = black, Specular = 100%, IOR = 1.586, Diffuse Transmission = 15% grayscale, Specular Transmission = mapped with B&W Color Gradient node (View Direction) > (Input) Color To Number node, Output From/To = .84/1.

• LED Dome Covers (Epoxy):
Dielectric material, IOR = 1.603, Transmission = HSV (130,96,100), Color Density = 2, Roughness Transmission = .02. (For a red LED, use Transmission = HSV (359,96,100)).

• Diode Lights:
-Illumination: Point Light Diffuse material, Color = 9500K, Power = 28 lumen, Radius = 3.
-Appearance: Emissive material, Color = 9500K, Opacity mapped with B&W Color Gradient node (View Direction), Intensity = 280, only "Visible in Reflections" and "Two-sided" enabled. (For a red LED, use Color = 2000K).

• Reflector:
Metal material, Color = 97% grayscale, Roughness = .0075.

Cheers,
Eric

mattjgerard · March 26, 2018, 06:05:49 AM

Eric, that is exactly the look I am going for. After my original post, I started playing with the plastics more, and was getting close, but this pretty much sews it up.

I am book marking this and revisiting the project this week. And thanks for all the specs, and actually for not including a bip file, as I really want to build this up by hand from scratch using your specs and see if i can duplicate it. Doesn't help me learn if I just open a file and copy/paste materials.

I'll post back when I get my images rendered. Cheers mate!

matt

INNEO_MWo · March 26, 2018, 08:38:55 AM

The ninja is back. Eric, thank you for this solution. I didn't had the time for a detailed scene with realistic models. Can you share your KSP? This would help a lot (even I am capable to rebuild the materials with your specs)

Good job!

Cheers
Marco

bdesign · March 26, 2018, 09:27:43 AM

Quote from: mattjgerard on March 26, 2018, 06:05:49 AM
Eric, that is exactly the look I am going for. After my original post, I started playing with the plastics more, and was getting close, but this pretty much sews it up.

I am book marking this and revisiting the project this week. And thanks for all the specs, and actually for not including a bip file, as I really want to build this up by hand from scratch using your specs and see if i can duplicate it. Doesn't help me learn if I just open a file and copy/paste materials.

I'll post back when I get my images rendered. Cheers mate!

matt

Thanks, Matt. Look forward to seeing your renders. I've now attached the .ksp per Marco's request.

Cheers,
Eric

bdesign · March 26, 2018, 09:29:15 AM

Quote from: MWo on March 26, 2018, 08:38:55 AM
The ninja is back. Eric, thank you for this solution. I didn't had the time for a detailed scene with realistic models. Can you share your KSP? This would help a lot (even I am capable to rebuild the materials with your specs)

Good job!

Cheers
Marco

Thank you, Marco. I've attached the .ksp to my original post.

Cheers,
Eric

Eric Summers · March 26, 2018, 11:25:15 AM

Wow Eric, that is really great! I'm bookmarking this too if I ever need to reference it! I really appreciate the detailed explanation you gave, these are the sorts of examples that really help me improve my skills. Thanks!

bdesign · March 26, 2018, 11:53:24 AM

Quote from: Eric Summers on March 26, 2018, 11:25:15 AM
Wow Eric, that is really great! I'm bookmarking this too if I ever need to reference it! I really appreciate the detailed explanation you gave, these are the sorts of examples that really help me improve my skills. Thanks!

Thanks very much for the kind words, Eric. Glad to hear it is helpful, and...you're welcome!

Cheers,
Eric

mattjgerard · May 04, 2018, 10:20:13 AM

ok finally got back to this project. I have been working with it all day, and have been learning a ton. FIrst off geometry matters! I was struggling trying to replicate what you had with lighting and material settings, until i figured out that of course my geometry was different than yours. The LED epoxy pieces and the clear round bits specifically. My LED's didn't have any thickness the way the CAD file came in, and that made a big difference in the transmission settings. Same with the clear lens parts.

But after some tweaking I think I got a good set going on. The Emission and Point light settings were different for each color, as the intensities varied and that was to be expected.

I could not get the diffuse transmission of the clear plastic parts to pick up the color from the point lights reliably though, but that might be because of my render settings. I was going back and forth between the experimental and regular product modes, and turning caustics on and off. I lost track of what the settings are that I ended up with

BUt its on the render server now, and I will post some before and after PS work on monday when I get back to work. Its going to cook for a while over the weekend.

Thanks again, and I appreciate the time and explanation. Looking to learn more about the advanced lighting stuff at Renderworld.

bdesign · May 05, 2018, 10:07:57 AM

You're welcome, Matt. Definitely need to have caustics enabled for the light transmission to work.

Cheers,
Eric

mattjgerard · May 10, 2018, 01:14:10 PM

Well, here it is finally- Took a couple detours from my intended path to get where it is, but I think it turned out ok. There will be more of these products to do, and my goal is to make each one just a bit better than the last one. Thanks to everyone that took the time to put in their tips, i sure did learn a lot from this one.

There was some post work in photoshop to enhance the glow and richen up the colors a bit to match the old renders that were done out of 3dsmax in Final Render. Everyone agrees though that the keyshot ones look much better.

mattjgerard · May 10, 2018, 01:25:53 PM

And here are some others from the same series-

Not as exciting, and the glows on them are a result of corporate decision by committee. I don't like them, but its a small concession. All the colors are achieved by passing through a single cloudy plastic material, so when they are turned off they all look the same, and All I have to do it change the material of the light object inside.