How to distort reflection on a even surface ? (without bump though)

[AlphaShow]

Greetings guys,

im struggling a little bit with some experimenting to achieve a effect i saw recently on marmor stone. There is some kind of weird reflection going on, where the stone is a even plate (picture will guess u more) but the reflection (idk maybe from a lamp or outside what ever lol), the reflection has some type of distortion.

Well then i thought like :“Yeah, for sure easily done with a bump map to control the way it reflects … but wait … that plate is even.”

You guys got an idea how to get this type of material done ?

Thanks in advance,
take care ! <3

PS: I know, the way the plates are placed are creating this distorted effect, but not every reflection is made up from the placement of the plates, i u get what i mean

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[Modron]

just because it looks flat to your eye doesn’t mean it’s completely flat. the distortion is caused by subtle uneven-ness of the surface.

[AlphaShow]

Okay, lets say im wrong.
what if i wanted to create such a material out of curitosity ?
How is it done ? :S

[Secrop]

The normals must have a very subtle variation. For example, a noise texture and a bump node are enough, but the bump strength should be something around 0.001/0.005.

[AustinC]

In addition to the bump strength being low, you want to use a normal map (procedural or image) that has large-scale variation, not fine variations. It should look wavy, not noisy. Here is an example image that would probably cover an area of 4 tiles, maybe more.

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[AlphaShow]

Sounds not so bad in the idea, but i have testes out ur solutions (thx for that btw), but unfortunately, they won’t work.
Neither with low Bump settings (there is no distorted reflection at all :S) or with the texture which u had provided. Only if i go insane with the bump value, eventually reflection will start to twist and whril and so on. But i guess to answer my question, there is no such a way i mentioned, right ?

But maybe im also to retarded to set this material up and u guys can handle it in about 2 min to proof that it’ll work xD Go ahead if u got some time guys

[JohnVV]

some of the variation is in the laying of the tiles
you can NEVER lay tile PERFECTLY

there will always be a bit of variation in the grout and mastic used
then you have the low frequency noise of the concrete pour
these are NEVER perfect

there will be some curvature to the floor
– and if LONG enough the earth’s curvature is see able – Atlanta airport

so individual tiles will have a 0.01% to 0.001 % tilt in the Z for the X/Y
and each tile will have a tiny bit of “non flatness” to it
but also a over all undulating of 0.01 to 0.1 %

[AustinC]

Could you post your node tree for the material?

[AlphaShow]

@JohnVV

Mate ofc nothing is clear even, I get that, but if I try to stick with small amount of bump, let’s say 0.001 or 0.005 as mentioned above, i won’t get any curved reflection at all. Im just curious if there is a way to simulate a reflection that isn’t depending on the surface.

@AustingCPrescott
I give you my whole blend file for this <3
untitled.blend (471 KB)

Notice though, I’d setup the normals with 1 in strength

[AustinC]

I will take a look at the file.

Also, you could use a reflection map with a distortion applied to it (add a noise texture to the reflection coordinates connected to the reflection texture). That would be a very quick and dirty method that would give decent results. Unfortunately, it would require an image of the reflections. You could create one from your scene, but it gets complicated quickly if something in your scene is animated.

[AustinC]

I removed your lights and added an HDR environment map. The reflection is very distorted with higher detail noise.

[AlphaShow]

Never really heard of an reflection map though, is it bakeable from the current scene ? Some enlightment would been awesome.

And yeah, thanks for checking my render out, i will test that right now

[AustinC]

Here it is. I added some compositing and some other minor details to the scene for aesthetics.
That image that I uploaded was just an example. It wasn’t an actual texture. I used a noise texture to create a similar effect across the entire floor. But, I adjusted the settings to make the noise look similar to the image I uploaded rather than similar to static.

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[AustinC]

A comment on the bump strength: real life values, especially percents, are mostly out of context here. It depends upon the scale of your scene and the distance settings. If a BU in your scene is 1m, then the bump that I applied was 5mm, which is actually quite a bit. But, normal maps are not actually displacement, so it doesn’t quite work out like that.
I did a test where I used a displacement modifier, and a variation of only 2mm produced a similar amount of distortion.

Considering that your floor is 14mx14m, I would say that 2-5mm is a realistic variation for a very flat surface.

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[RickyBlender]

interesting idea here

how did you make the floor texture ?
just an image with some square rectangles then added this noise ?

would like to experiment on that one

mind you some floor may have local variation convex or concave
which cannot really be represented like that

thanks
happy bl

[Secrop]

the small values of the bump strenght are related to the scale of your scene. If you’re using 1BU as 10m than a small value is good, but if 1BU=10cm, then the strength must be bigger.

[AustinC]

Okay, reflection textures…

As far as I know, a reflection map will not work with a normal map. You need to use physical displacement for the reflection map to be distorted. Also, for roughness, you need to blur the reflection map directly. So, it has some disadvantages, depending upon what you want to do. The reflection texture is just an HDR. Search online for how to make an HDR image from a scene in Cycles.

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[AustinC]

interesting idea here

how did you make the floor texture ?
just an image with some square rectangles then added this noise ?

would like to experiment on that one

mind you some floor may have local variation convex or concave
which cannot really be represented like that

thanks
happy bl

If you look at the blend file that AlphaShow uploaded, you will see. It is just a white glossy plane for a floor with a grid of rectangular mesh lights above it. Everything you see is merely a reflection of the scene. The distortion results from the unevenness of the plane’s surface that is caused by a normal map. In the images that I uploaded, I had just replaced the gray background with an HDR environment image to give the plane something more detailed to reflect. Otherwise, the distortion is difficult to see.

Actually, convex and concave normals are extremely easy to create. That is the entire purpose of using a smooth bump map. You can make the surface normals in whatever directions you want.

[Secrop]

a little play around before sleeping. Not at all optimized but the basic idea is there. (the noise bump is 0.037 and I still think it’s too high,… well the whole bump is exagerated!)

http://www.pasteall.org/blend/41899

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[RickyBlender]

I tried file and it looks to me that all the lamps are reflected only on a small portion of the floor
so not certain why !

but I doubt that a floor would make such bad reflections I mean unless there was an earthquake not long ago LOL

happy bl