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I am testing out some materials and put together a simple wine scene from some downloaded assets.

This is the render:

Render

Anyway, there are parts of the render that look pretty unnatural. I've pointed them out here:

Flaws

  1. The wine glass bottoms are unnaturally reflective. They almost look like metal.
  2. There is some weirdness happening with the wine glass on the left.
  3. There is a lot of noise only in the wine bottle side where it is reflecting the wine glasses.

Example of the noisy reflections I'm talking about (this is even after Optix):

Noisy Reflections

Here's the glass shader I'm using for the glasses:

Glass Shader

Here is my render setup and light paths:

Render Setup

I've deliberately cranked the Gloss, Transparency, and Transmission values to 32 after watching a talk about rendering glass accurately here. I've deliberately disabled caustics because well, cycles sucks at them.

Anyway, my questions:

  1. How can I fix the unnatural reflections in the bottom of the wine glasses?
  2. How can I denoise the reflections on the sides of the wine bottles?

Thanks for reading and for any assistance!

Edit:

Here is the blend file. I had to go with Dropbox because the file was too big for Blend-Exchange. Feel free to tinker with it and optimize anything.

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  • $\begingroup$ You could probably strip out the images and send it through blend-exchange. The glass on the left looks fine to me, there appears to be some of the background void reflecting in it. That IS how the stem of some of those glasses reflect, with a bowl shape like that. Are the glasses intersecting or coplanar with the floor? $\endgroup$ – Allen Simpson Dec 4 '20 at 2:09
  • $\begingroup$ The glasses are not intersecting with the floor, and are co-planar. The base of the wine glasses are the one big thing that sticks out to me as odd. I can live with the left glass, it's actually not as bad as I thought. With regard to "background void" - I don't know how this can be since I'm using IBL as well as geometric lights. $\endgroup$ – Jay Dec 4 '20 at 2:22
  • $\begingroup$ add a hdri to scene, try several ones until you get a nice reflection, remember to make glass look less weird, use an hrdi to fake the reflections, as well if there are any objects surround it will get reflected as well in the glass... $\endgroup$ – Michael Ben David Dec 4 '20 at 2:27
  • $\begingroup$ for the noise you need more samples. Looking at your settings you are using a lot more samples for preview than for rendering, that doesn't make much sense. Use less samples to keep the interface responsive and more samples to have less noise on the render. $\endgroup$ – susu Dec 4 '20 at 2:27
  • $\begingroup$ HDR only makes sense if you get an HDR that is a photo studio with lights for highly reflective objects... $\endgroup$ – susu Dec 4 '20 at 2:28
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A few comments:

  • The bottom of the glass is flat, making a horrible thick mass of glass. Most glasses are concave like this:

enter image description here

enter image description here

  • Use more samples for the render and less for the preview (to keep the interface more responsive and get better quality renders)

enter image description here

  • Use more light bounces

enter image description here

  • Turn Off ambient occlusion. In cycles you don't need it.

  • To have less fireflies bring down the indirect light clamping. Most fireflies come from indirect sources.

enter image description here

  • In my opinion the shader you are using doesn't improve the results of a regular glass shader. enter image description here

  • Don't use overlapping geometry, it will only yield problems, like Z-figthing, where the depth buffer will have a hard time differentiating faces that are close together.

enter image description here

Same thing with the labels, for very thin paper it is easier to work the materials part of the bottle and not as separate objects.

As for the lighting:

It is hard (I would dare to say that is impossible) that you will find an HDR environment that suits the scene perfectly, as lighting glass and highly reflective objects is an advanced task that requires careful planing of the reflected objects on the scene. Remember that you are not lighting the scene, but creating the reflections that will bring out the qualities of the objects depicted (reflectivity, opacity, transparency, shape, volume, roundness, etc).

How can I render objects with very shiny surfaces?

Take the advice from that link, and you disconnect the environment and start trying a single light source at the time. Make a single very big area light and play with it so that you understand what it does, how it is reflected on the objects and how the shapes are revealed,

enter image description here

enter image description here

Once you find a suitable placement for it, and only then, add a second one and evaluate the results until you are happy. Bring in only as many lights as you need for the effect you are after. The more sources you bring in the more shadows and reflections you will have to control, so be judicious and spartan when it comes to lights.

enter image description here

Use also black elements to create dark reflections among the bright sources.

There are countless articles on the internet on how to light and photograph wine, glass and shiny objects. Do your homework and learn from those who charge a fortune to do that (and don't forget to have fun doing it).

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  • $\begingroup$ related: blender.stackexchange.com/questions/48659/… $\endgroup$ – susu Dec 4 '20 at 3:35
  • $\begingroup$ As mentioned in my prior comment, I am using a lot more samples for preview because I have a very fast machine and I like to let it churn out more samples if I just sit there. It doesn't degrade interface responsiveness for me. I always max out my samples on a final render to anywhere between 1000-2000. $\endgroup$ – Jay Dec 4 '20 at 3:49
  • $\begingroup$ You need more samples on the rendered image, however many you want on the preview is not so relevant. $\endgroup$ – susu Dec 4 '20 at 3:51
  • $\begingroup$ Also, clamping can be detrimental to your render. Yes, it can reduce noise, but it can dull your highlights. $\endgroup$ – Jay Dec 4 '20 at 3:51
  • $\begingroup$ "You need more samples on the rendered image, however many you want on the preview is not so relevant." - I know, I just told you I max that value out when I'm going to go for a final render. $\endgroup$ – Jay Dec 4 '20 at 3:52

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