Cineversity

Was just wondering if anyone has had any success is creating a surface that mimics the type of plastic you get drinks caps made from. Been trying to get this to work but SSS give that kind of feel but only lets through light rather than actual transparency, i think SSS in the luminance channel would help in the final effect but isn’t sufficient on its own. Putting SSS in the transparency channel cripples the render times and doesn’t achieve what I’m after also.
I’m trying to get the screw thread and details to show through.So any help would be appreciated

Hi Mikest,

Do you have an reference image of the effect you like to achieve? A good reference image with the light effect you are after is always a good idea to have.

(Fo the sake of communication a simple web-link to an image will do. Normally I wouldn’t use unknown 3rd party material, as one never know what happen to the image, but if the link provides the data you have in mind, fine with me)

A normally clear plastic cup with a dull surface or “Styrofoam”-like? Not that I have standard solutions for each of them at all, but what your idea of a plastic-cup and the effect is maybe different to my idea about.

SSS will mimic scattered and caught light in the material. Perhaps you try a mixture of some passes, like an additional “Backlight” shader as extra pass and mix it in Ps or Ae.

All the best

Sassi

OK, if a reference image is not available, perhaps you might share your model with the light set up. Just to say anything about the SSS without being specific would end up in the same text as in the manual.

P.S.: I added an image to support the “obvious question” from the thread’s headline, just in case.

cheers sassi,i posted just before leaving work so heres the link to an example
http://www.sonicscoop.com/site/wp-content/uploads/2014/02/vitamin-water-zero.jpg
https://24hourwristbands.com/components/com_virtuemart/shop_image/product/ren_517a98cc3601da.jpg

the basis of the shader should be the thicker the plastic the less transparent it is, so from those example images where the thread of the cap is you can see the plastic is less transparent.

here is SSS in the luminance channel and 66% transparency with 30% blurriness which is kind of close but not right as i don’t really want or see much blurry transparency in the real thing, also the render time makes it unusable for print res as this screen Render Region took 1 hour to calculate.

Hi Mikest,

What I see is that you have a result—but the render-time is over the limit for your needs. As I have no model here, nor endless render-farm-options, my suggestion is here to find the source that pushes the rendering that high. Exclude things (Transparence blur!) to see how it would work. Some results are possible only with the render-time already established, some other scenes might not suffer if some parameters lowered. In other cases, “post”  need to balance what the rendering couldn’t handle.

What I did with my morning so far was to search for alternatives. I’m not a strong believer that only one way exist and certainly not at all a fan of ready made stuff. SSS sits kind of between for me, it allows to do renderings which are difficult to “fake” in some instances. But to rely only on it is not my ideal, as I do animations, most time consuming things are out of the question from the start, especially since we go strong to the 4K / UHD era. No time for things that can’t be optimized or faked ;o) [Well, that is just my point of view.]

My suggestion, as I mentioned it above is based on multi pass, or call it separate passes, as it is not doable in one rendering. I created an object with similar features (thread and structure) and tried to figure out how to do it without SSS.
MY idea is here to have the inside of the object as separate object and render it without the outside. I assume that modeling is not at all a problem for you, given the example. I did several passes with transparency (no blur), with reflection and one with FOG as the only channel. Each time with a straight alfa, so I have full pixel values. The idea is to blur in Photoshop the inside “parts” and limit the blur of course with the outside Alfa-channel. Note that for the inside you need to use after blurring the outside alfa.
The FOG result is mixed as well into it, perhaps very little. To have a depth map of the inside object might help a little bit as well.

Keep in mind that some objects can have an Environment-Channel based refection. This could be based on a 360º/180º rendering from the center of the object (QTVR) and have that blurred before use (Blur it and use the Offset option in Photoshop to blur the seams appropriately)

For the transparency, I would use the “Absorption Color/Distance” Option to a certain degree as well. A little luminance perhaps as well for the inside object, as light is scattered there. In the light sources you need to adjust the softness (area) of the shadows, to get the SSS effect for the material simulated.

Perhaps you have some other observations, and adjust internal refection and fresnel option accordingly. Global Illumination for the inside sounds good to me as well, just as an other option. Another option of this set up is that you can color correct each layer: If your impression is the the light [while traveling] becomes warmer or colder, just use an layer adjustment and pull the values you need in.

Yes this is way more work, but you gain the option to adjust each “quality” of the material in Photoshop in realtime. ... or you can ad perhaps something later on. If you compare that with extreme Render-Times otherwise, you might get the idea. (Perhaps each extra pass is rendered on a new frame, with Step as key interpolation, as it is for print, that might save some time)

As we talk here nearly exclusively about light, 32bit/c float for the compositing might be mandatory, to stay linear. Which disables sadly a lot of options in Photoshop. If you have access to NUKE or other full 32bit/c apps, give it a shot there perhaps.

While I type the last hours of experimenting down, I got the idea that the team of “ROBOT” (Will Smith) did the same for the robot face parts. Control in realtime has its advantages.

Good Luck

Sassi

Example images are more sketch. I could even double the “Inside Object” and blur one more than the other ...etc.

cheers for that sassi, i guess my thoughts of this not being doable in cinema in one shot is true, my main 3D program is lightwave which i can do this easily using a surface thickness gradient and was hoping i could do something similar in cinema,(where i work like me to use cinema as much as possible as the other people here that do 3D only know cinema) i was hoping that there could be a way to utilise the path length of the SSS in the transparency channel some how, maybe using expresso but i have no knowledge of expresso yet.
Also this cap does actually go on a bottle, which also has the thread modeled which needs to be visible through the cap plastic, and that is also transparent so the multi pass idea i dont think will work as blending all the passes for each bit would turn into a nightmare and i’d also have the retouching and colour work to do on the main render of the bottle.
Doing another render test now and it seems like the combination of SSS and transparency is slowing things right down, transparency blur just exacerbates it.

Hi Mikest,

The thickness evaluation of the material is a standard option in the Transparency channel. Absorption Color/Distance, see above. Here you can set up the depth and the color of the effect. No SSS needed. BTW, SSS: The lower the value [Path-lenght] the longer the render time. Multiple vs Single, a huge render-time difference, as is if used [in my experience] if used in the transparency channel.

I showed you an alternative to get this done. Yes the bottle can be part of it. And I certainly didn’t ignored it in my thoughts here, but to understand the procedure, I have shared everything.

My suggestion is, as you haven’t shared any scene, check your set up. To say it is not possible in one shot in C4D is not true obviously, as you did one, but your render-time wasn’t to your liking. Just to be fair.
For client work, I can see a reason to not share the file in public, perhaps you get in touch with the support. I’m interested in Forums work, to solve problems that help many other people. Maybe it is the set up that slows things down, how can I know from an image alone.

XPresso has no tools to get at all into render-algorithmn options, like depth, etc.

To use a fixed length, perhaps a split of the model might help to get it in one pass, if that is what is needed.

If you can do it in Light Wave so much faster, then you have your tool.

Take care

Sassi

the absorption colour/distance doesn’t work on the actual transparency of the material/surface. the absorption colour is only applied once the rays travel the absorption distance, this may give the appearance of an object being less transparent but it merely becomes more saturated with colour and as such stops light/rays passing through an object and ends up appearing darker. Again this doesn’t achieve what i am after as i have already tried that and get the same result if i just use a dielectric material in Lightwave. We are talking about calculating transparency based on the thickness of a material
Yes Lightwave does produce exactly the results i require and was used in the end as cinema simply couldn’t do the same job and could not get anywhere near the time of the render. Our work is high res for print and is usually a minimum of A2 in size so i am used to long render times but cinema seems to trip up when it comes to transparency at high resolutions.
The reason (as i stated before) for trying to get this job done in cinema is there are other users that may require those assets and they only know cinema.
When i get some down time i will upload a scene that you can pick at and maybe find a better resolution in cinema. But the idea was to try to create less work not more.

Thanks for the feedback, but to suggest features for C4D, this is not the forum to do so.

Please use http://www.maxon.net/support/suggestions.html

Good luck.

sorry i wasnt trying to suggest features rather try to get cinema as it stands to create a commonly found material

This function, as you describe it is not possible, Mikest. Certainly, it wouldn’t hurt to have it. ;o) Light-Wave has a differen’t set up of how materials are done, if I recall my last version/license of it, but that is a long time ago, 14 years by now(!?)

The more people would request such a feature— the more it moves up in the hierarchy of the developers to do so.

All the best

Sassi