alucobond and stucco - 2 materials i stuggle with - how do you...?

[simonm]

Hi all

 

Firstly, Alucobond is Australia is a commonly used product in architecture and I have struggled to replicate this accurately. Has anyone had such luck? If so, what is your set up? I recall Jeff Patton had a tutorial on this, but it was using mental ray (i believe he doesnt have it on his site anymore). Anyway, see attached - would be interested to see how you guys tackle this material?

 

Also, stucco. Although simple in form, i still am trying to master the aesthetics of this one. Rather than a simple bump, i tend to use composite maps and blend patchy textures to give it bump and specular irregularities. It works, then i feel it needs more development. Its used on 100% of every job I do so no wonder im always trying to master it. Im a bit of a perfectionist and I always try and improve my materials. What are your methods of creating this?

 

heres a version of stucco that shows irregularity and a patchy surface:

 

Thanks and looking forward to your response

[Nic H]

i think stucco is about making the right bitmap and associated bump / displace, specular and reflection maps. even though it looks completely matte a subtle glossiness can really help to add depth to a flat wall.

 

as you need it so often could you photograph a few types in overcast and soft light and use that to make a nice high res 5k tiling map? use a couple of them and blend using vray dirt to get definition on crevices and edges?

 

the key to alcubond is to use a vray blend material as you need a wide flat highlight combined with a sharper more defined reflection at glancing angles. the base layer might be a 0.5 glossy mid grey reflective material with a larger soft noise as the bump map to break up the reflection a bit. the coat layer might be a 0.95 nearly white with a fine scratch map as a bump. you will need a decent diffuse map as well with some variuation to get it looking believable.

 

in the blend slot use a falloff map i suggest fresnel and then adjust the IOR and curve to suit.

 

the reflected environment will also be very important in this material.

[simonm]

thanks heaps for your response - makes complete sense except 1 thing......

 

"you will need a decent diffuse map as well with some variuation to get it looking believable"

 

I was under the impression the alucobond is mostly procedural?? What would I use in the diffuse? I thought it would have just been a solid colour?

Edited October 12, 2014 by simonm

[Zdravko Barisic]

Your images, you've been posted, are what you done or what trying to achive?

[simonm]

Hi - theyre what im trying to achieve

 

Your images, you've been posted, are what you done or what trying to achive?

[Chris MacDonald]

Alucobond is fairly easy, but there are lots of different ways of achieving it, with and without blend materials and so on. If you look at it, it's fairly metallic (IOR probably 1.8 and higher) and the reflections at glancing angles are pretty sharp, but their glossiness falls off as the angle of view gets closer to 90 degrees (viewing flat on).

 

One way of doing it might be:

 

First things first, set up the diffuse colour; either flat grey or a falloff that gets darker around the edges. You can use the "amount" parameter in the "maps" rollout of the vray material to control the mix between the diffuse colour and the map if you need to find a happy medium between the two.

 

Next, the reflections. Set the reflectivity to pure white and make sure fresnel reflections are checked. Set the IOR to whatever you feel suits; likely to be 1.8 to 3. Because it's metallic I would also change the BRDF model to Ward.

 

Now get an idea for how matt you want the reflections to appear by changing the glossiness down to whatever you feel looks right; I usually arrive at around 0.6 or 0.65... But this is where it gets interesting, because reflections at glancing angles are much sharper. To achieve this you can use a falloff map in the glossiness slot.

 

The falloff map defaults to pure white, and pure black - but obviously pure black is going to give you a reflective glossiness of 0.0; something that is both nonsense AND going to take a long time to sample. To get the reflections to look like the 0.6 that I suggested earlier you'll have to do a bit of fairly simple math to convert the RGB value to a decimal value:

 

(255/100) x 60 which should give you a value of 153. So change the black colour in the falloff to 153 and you'll see that you start to get some more convincing reflections.

 

Next add a very subtle bump map to create minor surface deviations and you're all set to go.

 

If this wasn't enough you could also try putting this material inside a vray blend and create a coat material with fairly sharp reflections and smudges, etc. Sorry if it's all a bit much, I think it would be nice and easy to understand if this were in a video - I might do one tonight, maybe.

[RyderSK]

Seems like everyone gives a tutorial to single exact Alucobond, but it's basically just tile with various surface options, and its the surface options that decide how the material looks and therefore how you re-create it in 3D.

 

I would say the above tuts works with only the simplest, "Flat color" option, which is glazed paint.

 

Then they also have various other options on top of the tile:

 

Metallic color = CGI Metal

Metallic color + Glaze = CGI Blend of Metal + Thin film of glass

Metallic color + Anodized layer = CGI Metal with rough glossiness

Spectra/etc.. = Carpaint

 

And these material vary a lot by how they work, metals DON'T have diffuse part (NONE=Black=0 RGB ) and their color (how we perceive the color) is actually 100perc. their specular (often tinted) reflection. To simulate is easily, what you perceive as their average luminosity is what you put inside reflection slot. Or Because Vray doesn't have complex IOR (n/K) you can get close by working in {4-40} range by eye-balling, or doing a curve inside reflection slot (with base reflection being what you perceive as the color, and sharp fallow at the towards pure white, a 'grazing angle' reflection.

 

I always first think of how material works in real-world according to physics, but then I simply observe the behaviour by eye. The rest is then simple mechanics to get it to work.

[simonm]

Thanks Chris - thats some awesome info - very detailed and easy to understand.... going to do that right away.

 

Juraj - thanks for your response... although i dont think I am at your level yet so some of what you said went right over my head.... can u dumb it down for me please ?

[RyderSK]

Ah, I said there is no single material that you can get tutorial for, which the people above gave you :- ).

 

Glazed paint color Alucobond, is completely different material than Anodized Aluminium Alucobond. One is plastic + glass coat, the other is pure metal.

 

Paint is Color (Diffuse slot) + Specular reflectivity with regular fresnel (IOR 1.6 or base reflectivity of 0.04perc. ).

Anodized aluminium is very rough coating on Aluminium metal, which is very reflective material (Specular reflective curve resembles IOR of something like 20+, or base reflectivity of 70+perc.). But it has no color at all, it's black diffuse, because all the ray reflect in specular way and none in diffuse.

 

Because of this, you have to think of exactly which Material is your Alucobond (or more likely, what is the upper coat layer ?) and not the brand name.

[Nicolai Bongard]

Jeff Patton did indeed have a alucobond material on his site, and in the comments section he also shared a vray material. These are the settings from that material: http://imgur.com/CJ4jPXm

[simonm]

thats the best response ive ever heard in my life...... haha

 

seriously though, thanks to all who have responded... i think this is a great thread, thanks to all involved...

 

Jeff Patton did indeed have a alucobond material on his site, and in the comments section he also shared a vray material. These are the settings from that material: http://imgur.com/CJ4jPXm

[Nicolai Bongard]

Im slightly confused, did i miss something? Or does the link not work for you?

[simonm]

no no im excited, it wasnt meant to sound in a sarcastic way - its a great link and exactly what I was after.....

 

Im slightly confused, did i miss something? Or does the link not work for you?

[Nicolai Bongard]

Great!