Problems seeing through transparent materials Tweet

[vmedium]

I am trying to get the back of this nexus 6 camera to look more like it does in real life.

I've tried tweaking the material so many ways, and I just can't get it to look transparent. I feel like I'm missing something major or maybe there is a bug?

(i'm using octane render 2.14, and the latest c4d plugin)

My Render:


Product Photography:


Thanks,

vmedium

[aoktar]

test the specular materials on some simple scenes to understand how works. Also be sure that normals of faces are correct.

[tehfailsafe]

Before spending tons of time tweaking down the materials, make sure your lighting is setup to match the photography. It looks like you might have one large soft light up above and left, but the inner circles of the camera ( behind the glass ) don't seem to reflect as many little lights as in the photo, and the graduation on the black back product shot is making me wonder what the lighting setup must have been like.

Then I'd think about how much that product shot was retouched in post, or even possibly be a shot from a biased renderer like vray, where you can artificially bump material settings beyond what a physically based renderer will do.

In Octane the specular material is physically correct representation of glass. You can adjust IOR and the other settings but ultimately real glass may not reflect the way the photo does. One trick we do for architectural renders is using a glossy material with the spec maxed and roughness 0.00001 so it looks like a mirror, then lower opacity until you get the amount of transparency desired. I'm not sure about 2.14 but in previous octanes with lots of windows and sunlight it used to render way faster too. I almost never use specular material base unless I'm rendering something that requires the IOR "bending" of light, like a glass with water in it, or a pair of glasses in a portrait, something where the difference of what's behind the glass and whats not behind the glass needs to be obviously different. If you just want some light reflecting off a transparent surface and even some color tinting, low opacity mirror like glossy mats should do the trick, and with a lot more control.

Only other thing I can think of is the model itself. There may be a super minuscule spherical shape in that product lens and yours might be too much of a sphere so it's picking up a lot more light reflections. Maybe flatting the shape out to be less curved might help?

[vmedium]

Lighting: Just to note with the reality of the product shot and the reality of reality. I have the physical phone, and it doesn't require special light to be able to see the detail behind that glass. It's just what it looks like in any level of normal light.

Geometry: I too was thinking maybe it had to do with a bend, so I grabbed all the points and flattened the surfaces and it still produced the same result. I also replaced with a complete flat disk at one point and it did the same thing. I've also added many lights, and moved many lights around and haven't been able to get it to look transparent.

I think the trick you are talking about should work though, and like you said render way faster. I'll give it a try and post the results.

[aoktar]

see this scene

[garytyler]

tehfailsafe, excellent and thorough response! thanks!

[vmedium]

I tried tehfailsafe's method. This didn't work initially. Then I moved the geometry behind the glass in a little more. This created a bigger gap. Then all the sudden at a certain distance it started working. (see attached)

Aoktar, I tried your file, thank you very much for that. Your file worked fine and rendered great locally even with a different HDR file. I used your glass material, and render settings and it didn't work in my file. Same problem, same blackness and lack of transparency.

With the fake glass material... It seems like the distance between the geometry is causing it to go black. If i move things apart, it works fine. I'll just have to deal with
it.

And lastly, any time I copy and paste something to a new file that has an octane material cinema crashes.

[FooZe]

...It seems like the distance between the geometry is causing it to go black. If i move things apart, it works fine. I'll just have to deal with
it.

So long as it doesn't cause any other artefacts, you could try reducing the ray epsilon, or scaling your scene up in size until the black goes away.
My guess is the distance between them is less than the ray epsilon value.

[vmedium]

Looks like I have some reading to do on Ray Epsilon. Thanks for pointing that out FooZe.