Bump not visible in glass.

[Mika]

Hi.

I'm still struggling to port some projects from 2.79 to 2.8x and little by little I have managed to solve the problems, but now I'm stuck and I don't know what to do.

Solved the problem of textures using Bump, Blender 2.8x adds a "displacement" in the middle of the bump and changes the Bump settings to Bump + Displacement. Changing to just Bump and removing the box of Displacement solves the problem, except for the glass, only that glass (well, some glases) has a bump texture and it's there but it doesn't create the distortion of lights that makes the pattern visible as in 2.79.

Using IOR with values higher or lower than 1.0 it's visible but only if the camera is very close to the material, as soon as it's a little more than a meter the glass looks completely smooth.

I don't want to use Displacement to save resources. Any way to make the bump visible as in 2.79?

* The red rectangles are to highlight what changes in the material between 2.79 and 2.8x, in theory it doesn't affect the final result.

https://steamuserimages-a.akamaihd.net/ugc/1485578440252804473/A70BF434E8B271C4378AA7400612412167A565B1/

[The Renderer]

Bump on glass only works through refractions, meaning you have to put in a realistic IOR, else it won't work (glass is something like 1.5 I think, google it). An IOR of 1 will not have any bump (and rightly so). If you want to "catch" the bump in your scene you also need to work with the lighting.

Edit: What I mean by that last sentence is that you can either get the bumps to show up via refractions or via reflections, but for the latter the light needs to be just right.


The pic on the left doesn't at all look like realistic bump, it looks like not enough transparent light bounces.

[Mika]

It looks bad because you are looking at an image taken from the viewport with 4 samples.

Another screenshot: https://steamuserimages-a.akamaihd.net/ugc/1485578440253513134/9E8D38B5BFBBAF287CB7D7206EB31A603446BF21/

- 2.79: Changing the IOR only makes the glass more blurry only. The pattern is visible at distances greater than ten meters and Denoising "keeps" it visible.

- 2.8x: Changing the IOR also makes it more blurry, it looks more transparent, however the pattern is not visible at greater distances, in fact in the screenshot it's possible to see how the upper right corner the pattern is barely visible (about 30 cm from the camera), in the tests the glass looks strange, as if it were melted, If I apply Intel Denoinsing the glass becomes completely smooth.

What I want is the pattern to be visible at all times, in the scene the camera comes to separate about 8 meters of the glass is visible in 2.79, with 2.8x using or not IOR it's not visible.

EDIT: The image on the right are renders from a while ago, both are 64 samples but in 2.83 I was testing the Intel deonising. Despite this without denoising it looks the same, the pattern is not visible. I have a render with 1024 samples, the camera is about two meters away from the glass and with Intel Denoising, the result is the same, the glass is completely smooth (with IOR at 1.3).

[The Renderer]

Not sure what you are trying to say. In your newest screenshot the 2.79 on the left looks bad, the 2.8 looks fine (the reflections). On the right, well, not much to see, it's too small and noisy, especially the 2.79 one.

Question: Your glass has a thickness, right? Cause refraction doesn't really work if your glass is just a thin polygon.

Also the pattern will manifest mostly by distorting what you see through the glass, so as long as you have a uniform color (like behind those doors) you won't see much either.

[Mika]

Sorry I'm not English speaking and I'm worse at typing so I use the help of google translator a bit.

My house, is literally an exact copy created in Blender 2.79 (I've been doing the house for almost 2 years now).

- Your glass has a thickness? Yes (rectangle), one side has the flower-shaped pattern, the other is a Voronoid to give a blur effect.
- What I want? See the pattern.

With blender 2.83 the pattern is only visible by reflections. If there are no reflections, the glass appears smooth.

In blender 2.79 this pattern is visible at all times, with or without reflections. This is what I want in 2.83.