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The Biggest Factor in Photo Real Architecture


yourfather
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Hello,

 

sometimes I seem to get incredibly photo real results but not consistently.

 

I think its texturing that im having a problem with. I have plenty of GI and FG. But the images still seem to lack photo realism.

 

Heres my question.

If i have high quality bitmaps, should that be enough or do i need to do something else to them? I use bump and reflection maps, are there others that are a necessity? For instance Fall off gradients in the reflection map, or normal maps?

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theres so much more to it than bitmaps - in fact, my belief is that its a healthy balance with textures along with:

 

composition - know your camera angles.

use of light & shadows

color balance

camera effects such as DOF have a strong impact

 

its an art in itself really - one that most of us struggle with. Ive had realistic results with projects i paid little attention on bitmaps and on the other hand, ive had a worse result on projects i paid TOO much attention on bitmaps.

 

well thats my 2 cents

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theres so much more to it than bitmaps - in fact, my belief is that its a healthy balance with textures along with:

 

composition - know your camera angles.

use of light & shadows

color balance

camera effects such as DOF have a strong impact

 

its an art in itself really - one that most of us struggle with. Ive had realistic results with projects i paid little attention on bitmaps and on the other hand, ive had a worse result on projects i paid TOO much attention on bitmaps.

 

well thats my 2 cents

 

 

Camera angle?

 

This you feel adds to realism?

You know what I find strange, I can't seem to get a room to be full of bright light unless I have the sun shinning directly into the window. I'm using light portals but the room never seems like a brightly lit room unless I have the sun at a low angle.

 

I should tell you that I use Mental Ray with a daylight system, FG and GI.

Edited by yourfather
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well partly yes - as i said is a healthy balance of all the elements - every bit helps. example - Particular camera angles may have a say on the light and shadow in the scene which helps with realism.

 

that does sound strange indeed. what is your shutter speed at? if you are using vray ensure its around 20-30 as a starting point.

 

Camera angle?

 

This you feel adds to realism?

You know what I find strange, I can't seem to get a room to be full of bright light unless I have the sun shinning directly into the window. I'm using light portals but the room never seems like a brightly lit room unless I have the sun at a low angle.

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Vray is awesome I love the results but right now I am using mental ray. However when I do use vray I was using a shutter speed of 100. I'll slow that down to 20 or 30 next time I'm in vray. And yes I see what you mean about camera angle. However the camera angle is usually determined by client requests. I usually have to change the sun or add sunlights (windows on the ceiling) to let more light in. But most of the time the image has a low light and somewhat flat quality to it. As I poor contrast. I usually fix this in photoshop.

Edited by yourfather
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You know what I find strange, I can't seem to get a room to be full of bright light unless I have the sun shinning directly into the window. I'm using light portals but the room never seems like a brightly lit room unless I have the sun at a low angle.

 

I should tell you that I use Mental Ray with a daylight system, FG and GI.

 

Can you post a screenshot of your render, lights and exposure settings?

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I'm a little reluctant to post pix of my current project because it's for a client.

 

There is a bit of nonverbal communication mess here, i'll try to clear it up:

Can you post a screenshot of your render settings, lights settings and exposure settings? :)

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90 perc. of "photo-realness" as in physically correct result, is technical not artistic.

 

Artistic stuff mentioned like angles of camera and lights, exposure, color balance, white balance, etc. contribute to aesthetical value of image, but not "photo-realness", unless we get into the age-old idiotic discussion that the "photo" part refers to aesthetical qualities of photography instead of what everybody actually means by it..

 

So, I've pretty strong opinions on photo-realness, as that's what I base my work on and I am quite obssesed by it it's that 90perc. is by properly computed LIGHT. Now, having fully unbiased renderer (such as Maxwell for example) that produces rather physically correct result by default helps, but of course, to "certain" (it will never be at same level, no matter what) level by any biased renderer as well, such as Vray and Mental Ray, but there are things to keep in mind.

 

I have most knowledge only of Vray, so I sadly can't advise in case of Mental, but for Vray this means keeping realistic values for used light sources compared to physical camera's set exposure, having sub-pixel off, because this will cut-off secondary reflective rays and reduces the overall GI levels, which to some (to me a lot) because rather noticeable.

 

Realistic tone-mapping: Fully linear workflow, linear rendered result, and natural tone-mapping through curves in post, ideally mimicking filmic curves to keep good midtones, contrast but also curb highlight.

 

Alligned albedos/hues/saturation of color inside materials. This is something EVERYBODY ignores, every times you download a texture source from internet, you shouldn't just slap them all inside scene and call it a day. They are taken at different exposure, have different white balance, different saturation,etc.. and this should be alligned before put together.

 

Realistic Albedos of materials: White is not RGB255, it's actually between 150-180 in most cases. Working other materials from there is rather experimental, but crucial.

 

Realistic Materials: Everything has certain reflectancy (30-60 on average, never 100!), everything has almost fresnel, effects (reflectance maps) should be subtle, some almost never (bump...)

 

Realistic Geometry: Everything is imperfect, croocked (use noise, noise everywhere, geo modifier, bump slot material,etc...),chamfered, detailed.

Proper UVs, materials direction.

 

High settings: Blurry Irradiance/Final Gather/etc. just don't cut it, the lack of details and simplified shadow gradients (which are too clean to start with) are just sore thing for our eyes. For realism, go high, or go home. Path tracing is prefered, but brute force solutions or even very high IR/FG maps can work to certain extent.

 

And last but not least, 100 little things that contribute to aesthetical quality, but it really doesn't concert realism, simple white room can be realistic and fake alike.

 

And the list could go one, photorealism in 3D graphics is SCIENCE of it's own, it's not simple, it's not this and that button, but 100 of things playing together well...and it's expensive, time and money wise ;- ).

 

Cheers, hope that somehow helps

Edited by RyderSK
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Hi Juraj, thank you so much for the informative comment. I hope you could enlighten me on a part of my workflow that's been bugging me for quite some time.

 

when you say

"keeping realistic values for used light sources compared to physical camera's set exposure"

 

I know for vrayIES lights we could always check with the manufacturer for the correct value, but what about vraySun ?

 

What I normally do when I create an exterior scene using a vray sun is to setup the vraysun first, keep the default values unchanged ( intensity multiplier: 1.0), test render and tweak the vray physical camera's setting to get the correct exposure for the image.

 

I understand though there might be no absolute wrong or right in a workflow, but I'd like to hear your input on this. Or maybe you already have a tutorial on your workflow that I'm not aware of?

 

Thanks for reading.

 

p/s: my apologies if this question is a bit out of topic, I just thought it's a great chance to ask since the thread is kinda related to figuring out the workflow to achieve photo-realistic images

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I think its texturing that im having a problem with. I have plenty of GI and FG. But the images still seem to lack photo realism.

 

 

More than likely it is the way you are setting up your actual lights in the scene. Geometry, textures, GI settings, etc.. are all all reliant on the lights you place into your scenes.

 

 

Off hand I would say the importance of what makes a scene photo-realistic falls roughly in this order...

 

1) Quality Light

1a) Post-Production Skills

1a) Quality Geometry

1c) Pre-Production Skills

 

2a) Image Composition, aspect ratio

 

2b) GI

2b) Textures

 

Again this is the first pass at a breakdown from my workflows in production. I will probably modify after mulling it over.

Edited by Crazy Homeless Guy
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Hello Juraj, could you explain this a bit, what do you mean by "align"?

 

That they are more or less at similar level concerning color balance. Ideally with same white balance (tough to do if one hasn't photographed it against anything white, ball or piece of paper, but usually one can spot color cast in histogram), contrast (there shouldn't be too much of contrast in the diffuse texture itself), shadow/reflection (these things are often baked-in the sourced photography, so high quality source which had cross-polarization done is ideal), saturation (ideally lower than looks good to eye in texture itself, it will mix with light later), gamma (all jpegs are sRGB 2.2 baked in, but some had adjusted gamma as means of contrast and this manifests in incredibly odd looking contrast), exposure (every diffuse texture should be at similar light level, this is something that has to be purely eye-evaluated, but again, can be noticeable if something sticks out too dark, and something too bright, take in mind that colors are darker before they interact light), etc.

 

I know for vrayIES lights we could always check with the manufacturer for the correct value, but what about vraySun ?

 

Concerning VraySun: Now Sun isn't particulary problematic, you can actually play a lot with these values, for example larger size and weaker intensity provides softer more diffuse light, akin slighly cloudy sky, much more eye-pleasing when used in Interiors, always very flexible compared to swapping HDRs in IBL.

It was more about going into extremes with classic lights and then adjusting materials. This falls under same category as no/improper LWF use, when people use just truly bad albedos (absolute white, absolute black, and near values) to get brighter look and more crushed shadows, something that should be done through tone-mapping or post.

 

Well, a bit more on that but I hope you see what I mean :- ) Materials go way beyond downloading texture from cgtextures and putting it in diffuse slot.

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