Author Topic: Juraj's Renderings thread  (Read 354096 times)

2019-06-20, 17:41:21
Reply #630

steyin

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Lovely images as usual.

Any chance you could share the setup for the bronze wall panels? I have a similar panel for an exterior cladding on a project but could never get the scale of the texture quite right...did you use a map or procedural?

2019-06-20, 18:01:05
Reply #631

Juraj

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I'll try to look it up when I get time, but I think it was regular bitmap, one for overall texture (in reflection slot), second material copy for brighter version masked with AO to make variations on edges.

But it's material I struggle often to make look good and I need to make it often and always make it slightly differently. Lately I even paint some of the variation in post-production (because we don't have curvature map and AO is not so good for this).
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2019-06-21, 13:37:16
Reply #632

John_Do

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An awesome set of images, really great work at every level.

@Juraj, I have some boring technical questions, I hope you don't mind ( I was asking you on Behance, I follow up here ) :

In general, how do you proceed to correctly match a material reference, if like me you often receive 1 material sample photo per material ? For example, how do you deduce from the photo if a paint is shinier at grazing angle, or if a wood material has a satin finish, or a coat/ varnish ?


- The wood floor looks so sharp and feels real. Do you used just diffuse / glossy / height / normal maps or there is a secret trick ?

- Glass with 1.52 IOR is often really too reflective at grazing angle to my taste, do you fake the IOR or the reflection level ? The one visible on the dressing cabinet is nicely balanced.

- The fabrics are also getting my attention, these are really nice and balanced. I often struggle to decide if I should put some reflections in my fabric materials, or keep it pure diffuse ( silk and shiny fabrics don't count), and it often ends with a mix of the two. Do you have any tips ?

- The "PBR rule" for albedo minimum black level is 50/50/50 sRGB, and I find really hard to follow it strictly. It is the MINIMUM black level, so these are the values for coal or some superdark material I guess. What would be a black plastic so, around 60/70 sRGB ?
Is this rule too strict or is my post-processing too soft on the dark tones ? 


On another note, the bed looks gorgeous, but I don't know how you get to convince your clients to accept an unmade bed. Just this fact alone is an achievement.


2019-06-21, 13:58:55
Reply #633

Juraj

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Hi John,

I'll write you more on this later but in brief (I need to finish building computer today):

1) I really try to get clients to send me physical samples. If they don't... well, that is pure "guess-work". But there are some general value that real architectural materials used by designers end up with, as they only use terms like "matte" (still at least 0.4 gloss), "honed" (for semi-gloss marble 0.7-0.8). As for grazing angle, I don't use this often, and the effect is actually so very subtle in reality that even currently the material simulates it rather well.

And clients often tell me what they want, i.e satin wood, or varnished wood. They would not forget something like this :- ). But if they don't, I go for the most common natural treatment. It's not bad idea to start with almost all materials around 0.6 gloss. Everything is rather shiny but gets toned down with surface imperfections from microbump.


2) Fabrics are indeed my nightmate and I long petition Corona Devs to finally implement "SHEEN" like in DisneyPRX. Because they really can't be simulated well with simple fallof or reflection. And yup, I do the same as you, mix of two. Because lot of times fabrics, the actual fibers are reflective, so it's not wrong to use Reflection on them, but they are also "hairy?" or how it's called,and then creates the subtle brighter halo at grazing angle.
So my fabric are often both reflective (0.1-0.4 gloss, but so it doesn't end up shiny, I use it together with strong bump/normal map to break this reflection) and also fallof in diffuse slot.

I experimented with anisotrophy but that really doesn't work well...to get true anisotrophy we need something like GeoPattern to create the natural multi-directional anisotrophy that fabrics exhibit.

I still hate them, fabrics are still the worst looking thing in CGI without custom BRDF. I hope we'll be able to use VrayScans just to get their BRDF from them and replace textures (it's possible there already). This way we could use material property from Velvet, and just use our bitmaps and colors. But for now... just what you are doing.

3) I follow it semi-strictly, i.e 90perc. I break the rules occasionally but not often. My blacks are indeed almost never lower than 50 sRGB, and if that looks too grey ? Then you're not using enough contrast in Framebuffer and post-production :- ). That's how blacks really look in reality.
But there are already some really black materials in worls, metals, coatings, super-fabrics...so it's not like some of them aren't 20 sRGB, just that 98perc. of regular materials arent.

Glass: Yup, we often fake glass. In the image of close you mention, the reflection multiplier is like 0.1... I consider it to simulate "polarization filter" :- ). If you want to do this physically correct, use RaySwitch Map or MTL. Have the actual GI be pure reflective, but visibility smaller. That is exactly what polarization filter would do. You would still get correct light bounce, refraction,etc.. but you will see more into the glass. Smart fakes are absolute necessity.


4) HAH, the bed. Everyone asks and here is the secret: We never once forced clients, ALL OF THEM ask for those beds. 5 +/- years, or when it was, we created the first messy bed just for fun. And since than, clients still ask for that bed, they literally put it into brief to use that bed (or other messy bed they have).

I am pretty sure some people would not like it, and it would be poor fit for hotel room, but many clients are far less conservative than we think.
talcikdemovicova.com  Website and blog
be.net/jurajtalcik   Our studio Behance portfolio
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2019-06-21, 20:55:42
Reply #634

John_Do

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Hey Juraj, thank you for these pretty detailed explanations, much appreciated.

The glass trick is smart, I will try that, at least to discover and use the rayswitch material once.

I'm a big fan of anisotropy for some effect ( wood grain, stains ), but it's tricky to define the correct balance with the glossiness, correctly mixing the two factor is hard. I've found the results interesting for velvet fabric, but improvable. For sure VRscans are way more precise but you can't compare to this, it's unfair :).

About this dark albedo thing,  I've downloaded few dark Megascans materials and checked RGB values,just after posting my questions. I shouldn't have done that, it raised up more new questions than answers ಠ_ಠ .The values are so low that I've doubt of my understand of sRGB / linear values.

I will not pollute your topic, so I've opened a new one in the right section.

2019-06-25, 13:40:21
Reply #635

Juraj

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Quick wip done last year from small in-house series. Modelling by our Kristina, mats&textures by Veronika.





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2019-06-25, 14:19:35
Reply #636

romullus

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This is freaking awesome! More please!!!
I'm not Corona Team member. Everything i say, is my personal opinion only.
My Models | My Videos | My Pictures

2019-06-25, 14:26:40
Reply #637

Rimas

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Dang, those car images are pure sex to my eyes right there!
A morning of awkwardness is far better than a night of loneliness...

2019-06-25, 16:25:51
Reply #638

Juraj

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Thank you guys :- ). I'll post up some crops later but otherwise not a lot of exists. These are quick wips of asset preparation for lot more ambitious project but life got in way and as tiny studio we had to focus on our core.

It's in backburner for now..
talcikdemovicova.com  Website and blog
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2019-06-25, 23:17:22
Reply #639

melviso

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2019-06-26, 13:50:42
Reply #640

Juraj

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Thank you kindly Melviso. Here is small sneak peek. From cold London, to sunny Mallorca ! And there will be new caustics...subtle, but where they would belong.



talcikdemovicova.com  Website and blog
be.net/jurajtalcik   Our studio Behance portfolio
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2019-06-26, 19:34:48
Reply #641

melviso

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Looking great, mate. Loving the lighting and soft shadows. Looking forward to the renders :- )

2019-06-27, 10:46:22
Reply #642

newages

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Very nice Pics!

Do you desaturate your HDRI's? I can see little color variation in your daytime interiors between sun and shade areas.

2019-06-27, 11:50:30
Reply #643

Juraj

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Very nice Pics!

Do you desaturate your HDRI's? I can see little color variation in your daytime interiors between sun and shade areas.

Do you mean generally in my daytime interiors, or the past two projects ?

I use mainly Sun&Sky, and soft boxes/reflectors, bounce cards in 90perc. Only 10perc. HDRi for interiors.
I do control saturation of both within certain range, enough to simulate move overcast version, never to create artificial B&W version though.

I did that (full BW) only once, the Jessica Vedel apartment where I used fully BW. That was unrealistic but with what I call "strong overcast" (cloudy with hint of very wide sun casting soft shadows in color similar to clouds) the color temperature difference could be less than 1000 Kelvin.
But usually even for overcast, it's more, like 2000, and I never go below such difference. You can get the effect by desaturating HDRi, having lower saturation of Sun if you want to simulate midday color but longer shadows for artistic effect, or simply just using weaker Sun compared to Sky. (like 0.1 intensity).

With bright spaces, good GI and well managed tonemapping (desaturated highlights), the hue difference can be very tame. Shade areas still receive bounced light from Sun so they will become blueuish only if they're less affected by such bounce, i.e darker material palette of space, etc.

Lastly though, I can have my images be slightly desaturated not just in highlights but overall as personal aesthetique in post-production. But it depends on projects.
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2019-06-27, 12:19:15
Reply #644

newages

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i like the desaturate highlights trick - gives a nice result