Can't see lighting inside glass cabinet

Hi :slight_smile:

I’ve been working on this scene for a while (first in Eevee but the layers of glass shelves behind glass doors were not playing ball at all!) and the one thing I’m struggling with is getting the down light to show up at the top of the glass cabinet. I’ve attached a screenshot of the Look Dev viewport where I can see that the spotlight is showing up but once I render it, you can see that it is not emitting any light.

Does anyone have any solution? I’ve also included a link to the Blend file so you can see my materials/ world settings etc

I’ll be very embarrassed if it’s just that I haven’t turned the strength of the spotlight up high enough, but I’m sure I’ve tried that already… here’s hoping! :sweat_smile:

Thanks in advance!


Glass (Refraction BSDF) is opaque to rays in Cycles. Either use Refraction Caustics or Transparency shader for lightpath/isShadowRay.

The vase is blocking the spotlight light cone.

Sometimes I’ve had very good success with just “the suggestion of glass,” composited into the scene. It isn’t real glass, it isn’t really transparent, but it’s an “Alpha < 1.0” superimposition to create a plausible visual effect consistent with glass being there. Other tricks are to reduce hue-and-saturation in the areas masked-off “behind” the glass. This wouldn’t work, maybe, if the “glass” was going to be subject to close inspection, but there are an awful lot of cases where it just won’t be. (Especially nice when the “glass” is going to reflect light but you don’t actually need to see through it, as in a window-pane viewed from the outside.)

“Cheating” Is Good. :smiley:

I loaded up your blend file and I can tell you offhand why Eevee wasn’t working for you. You don’t have any light probes. Eevee only counts rays that it can see from the camera, that’s why it’s fast. You have to “bake” the lighting with light probes.

Why tho, don’t clamp direct. Clamp indirect on 10-20 on interiors or your lighting will be seriously broken.

You had sobol. Change to multi-jitter. More time but less noise overall.

The hell, why do you set it so high if you’re not yet done with compositing stuff.

That’s a serious overkill. You’ve killed my 980Ti VRAM. If you want to use such high subdivisions - use adaptive subdivision. Do not ever do something like that because that vase had trillions of faces.

After cutting off those ridiculus numbers (I’ve put it on 2-1-2 for quicker renders) build time was like 10x smaller and I could actually render that scene.
Why two glass panels there?
Also, change that value there to 1 or 0.99.

And finally, a response:
All light goes up to the vase.

Ok, had a go at it. There is a few problems here, many not related to the specific problem:

  1. Replace the Cylinder thingy with a world environment map. That cylinder will block sunlight (infinitely far away) and probably not the most efficient way for Blender to handle. I used sky texture to light the scene and the skyline map for camera rays - this trick won’t work unless you fix the window glass (see #5 below).
  2. I set world strength to 29 and sun strength to 441 (approximate; I don’t have my notes in imported files). The problematic spotlight I set to 900mW (600Lumen/666, again approx), and gave it a 2700K temperature (2400-2700K typical for these kinds of lamps). I switched it to Point light and gave it a Spot IES file with narrow spread (StarFocused from Pixar). In a room with a lot of high energy sunlight bouncing around, this lamp will hardly show at all. Perhaps turn off the sun and expose for daylight instead, that will make it brighter.
  3. I turned off clamping. Never use clamping unless deliberately to fight fireflies.
  4. I used simplify to handle silly settings, I didn’t bother hunting for them.
  5. Caustics off, so everything glass like I handled shadows for - see previous post. The glass windows need to be handled with care; for glass like this I always use transparency + glossy mixed with fresnel. But you need to invert the IOR for backfacing faces. Glass should also have some green volume absorption.
  6. Speaking of which, many normals in the scene are off, and trying to fix them automatically is impossible because faces are separated. So you need to do merge by distance before fixing them automatically.
  7. Geometry in the TV bench is off/missing. Some of the sides consists of a single plane without thickness, meaning you can’t have correct normals. Ignore this if this is an optimized object where all unnecessaries are deleted deliberately.
  1. In addition to Sobol, are you sure you want min light bounces and min transparent bounces activated?
  2. The geometry of the lighted glass vase itself is problematic, with pinching at the bottom.
  3. The problematic light is problematic in the sense that you normally want the disk to be a camera thing only and let the lamp handle everything else. We’d want a disk lamp with radius (for shadows) with a sharp IES (no radius) that can also shoot like a point. Blender isn’t there yet, and I don’t think it will happen. But I set the emission geo to same effect and color temperature as the lamp.
  4. I also deleted lights that did nothing (off scene), and that odd interior light I assume was a compensation for complete lack of environment getting in.

Thank you for looking into this in such depth.

I knew it was a bit of a mess but I didn’t realise to what extent! I’m pretty new to Blender so all my settings are from various tutorials and google results which means I’ve just ended up with a hodge-podge of different settings probably not meant for the scene I was creating!

I’ve gone through all the steps you’ve listed and the result looks great- thanks :slight_smile:

Thank you so much for this. I really appreciate the detail you’ve gone into - it’s always helpful knowing what settings to change but it’s much more so when there’s some explanation behind it :slight_smile:

As I replied to Acrivec, all my settings have come from suggestions I’ve seen in various tutorials and forum posts so I guess it’s just become a bit of a jumble. It’s good to have an overview of the scene as a whole from one person- it’s made me realise how much I still have to learn!

Speaking of, there’s a few bits I’d like to ask you if you wouldn’t mind. I’ll just list the points I have questions about:

  1. I’ve found the sky texture, but I’m not sure what you mean by world environment map and skyline map?

  2. I can’t see the settings you’ve suggested for the spotlight, is this a node set up? I’ve found the IES files, they look great- I’ll have a play around with those

  3. Duly noted!

6+7. The furniture is imported from Sketchup which I know is not generally done in Blender but it’s okay for what I’m using it for. If you have any experience/ advice for doing this it would be helpful- I export it as a collada file and it always comes into Blender a bit of a mess.

  1. Probably not… I’m not actually sure what sobol is though, I just read in one of my frustrated googlings that I should enable it.

I think that’s everything, thanks again :slight_smile:

I’m all for cheating a little! :joy:

Thanks for this, I’ll bear it in mind!

Use LightPath/IsCameraRay to mix between the skytexture and the cityscape texture you had plugged into an enironment map node. Allows control over what lighting is and what you actually see.

Strength is either the power setting under light settings, or as Strength for the emission node / IES texture node- For color temperature, use the node Converter/Blackbody.

No, sorry. I hate Sketchup, so no advice from me there :stuck_out_tongue:

There are links in the manual page if you want to look further about sampling. Don’t blindly trust what others are saying (including me), it’s wise to read up on the subjects presented. Get a “feel” for it, not hard study.