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Exterior Rendering

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Exterior Rendering

Post Mon May 01, 2017 9:34 am

Was working on this for a small competition. But Contest was closed 48 hrs before scheduled deadline. Still a WIP and working on making it better.

Image

please click image to see complete picture.
flagus
 
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Re: Exterior Rendering

Post Mon May 01, 2017 12:55 pm

Hi Flagus !
That's pretty good :)
Can you tell us more about light settings ? It looks a bit flat, did you use a sun lamp and a sunsky ?
For a faster workflow and renderings, you can use separate parts too, like a rendering of the grass composited later with the rest of buildings,etc...

Olivier Boscournu __ riofranco design  Montpellier _ France   http://www.olivier-boscournu.com/

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Rio
 
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Re: Exterior Rendering

Post Mon May 01, 2017 9:15 pm

Hello Rio. Thanks for comment. Yes I'm using a sun lamp and also I'm using an HRDI for the rest of the lighting.

Could you give an advice to make the image with more depth? I was thinking of maybe using a grey image of the render.

Actually the grass rendered without decreasing my render time. The palm trees was another story. Maybe because of the different level of foliage.
flagus
 
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Re: Exterior Rendering

Post Mon May 01, 2017 9:40 pm

Hello,

I have the feeling that the sun light direction does not match the sky, reducing realism.

If the sun comes from a more vertical angle and a bit fron the left side (matching more the brightness from the clouds) perhaps it could be more realistic?
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David Bluecame
 
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Re: Exterior Rendering

Post Tue May 02, 2017 9:32 am

Hi guys :)
David is right, the sun light doesn't match wtih the sky. I noticed that the " sun position" addon doesn't work with Yafaray, it would be help a lot to match the sun light source into the HDR map and a " real" sun lamp. You can use too only a simple Yafa Sunsky and add a sky later in Gimp. Try too to get a more random aspect of the grass ( color, size and distribution), and of course you can render palm trees apart and compose it later.
Mostly use the render pass in Yafaray, it's very very useful, specially those like AO pass, Glossy,...

Olivier Boscournu __ riofranco design  Montpellier _ France   http://www.olivier-boscournu.com/

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Rio
 
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Re: Exterior Rendering

Post Tue May 02, 2017 4:53 pm

In any daylight scene, take always into account that there is usually a big contrast between areas lit by the sun plus the skylight versus areas lit only by the skylight. If an area lit the the sun+sky is in the middle of the histogram, then the same area lit only by the sky would be near black (between 2-3 ev stops in a camera light meter)
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Samo
 
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Re: Exterior Rendering

Post Wed May 03, 2017 8:22 pm

Hello everyone thanks for the different tips. Man I have so much to learn. I hope to be able to update this project during this week. I'm starting another competition today I have a slight chance to win so I'll go for it. Again thank you to all your comments.

I would be grateful to know how would you guys approach exterior rendering projects so as to make them as photo-realistic as possible?
flagus
 
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Re: Exterior Rendering

Post Wed May 03, 2017 8:32 pm

Hello,

I know nothing about architectural design, but from a rendering point of view my advice would be to try to get the lighting right, so it matches the sky and other "real" images around the model as much as possible.

For example in your scene, I think part of the problem is the angle of the sun does not match the sky/clouds and also that, as other users pointed out, the light dynamic range does not look right. For example, for a scene in the middle of the day, with the sun up in the sky, the building looks too dark and the difference between areas illuminated by the sun and the shadows is not the same you would have in real life.

I would suggest that you get a similar scene from a real building, where the sky/clouds are similar, and look at how light illuminates the building, floor, etc, and the brightness differences respect to shadows cast by that real building. If later in your 3D model you can "emulate" a similar lighting, I believe it will look more realistic.

Also, deliberate imperfections give more realism. For example if a wall, floor, stairs, etc, are too uniform and "too clean/good to be true", it reduces realism. Some dirt, broken or worn bricks, adding some smooth variability to image textures using texture layering, etc, can give additional realism through imperfections.

I hope this helps.
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David Bluecame
 
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Re: Exterior Rendering

Post Wed May 03, 2017 8:36 pm

Another possibility that you could evaluate is to get a *good* HDRI texture with a real sky + real sun with a very good dynamic range (where the sun is really bright compared with the sky). Sometimes to get such good HDRI you might have to purchase it.

Such HDRI used as IBL without other lamps would give you additional noise in the scene, but the lighting should be excellent and the result much more realistic. To reduce the additional noise you can use the IBL "blur" setting so the HDRI image is rendered "as is" in high resolution but the light generated by it is a bit blurred to reduce noise. You could also use the Clamp Indirect feature to reduce fireflies from indirect lighting of such bright sun.
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David Bluecame
 
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Re: Exterior Rendering

Post Thu May 04, 2017 3:11 am

Thanks for the different advice David. I'll surely apply them as I continue to work on the scene. I did just some small update. I increase the sun lamp strength which seems to be a mistake as some parts of the image seems darker.

Image

For a more high res pic:
https://drive.google.com/open?id=0B_u2k ... jRuY05jNjg

And David thanks for the latest release, works great.
flagus
 
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Re: Exterior Rendering

Post Thu May 04, 2017 3:15 am

Here is a version edited in Gimp where I brighten the image.

https://drive.google.com/open?id=0B_u2k ... VRKQlpuUkk
flagus
 
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Re: Exterior Rendering

Post Thu May 04, 2017 7:54 am

flagus wrote:I would be grateful to know how would you guys approach exterior rendering projects so as to make them as photo-realistic as possible?


First use an image of reference, will give you ideas about proper lighting ratios. Shoot a similar scene then analyze the histogram. Study how a particular material changes from sun+sky to only skylight and then look at the histogram. Tonemap your image in real time using a S-type curve in the Blender editor. Look for ratios in your histogram. Start from a 18 grey clay render. It is all explained here

http://www.yafaray.org/node/667

The image now is like lit with a lightly cloudy day where some of the sun like can go through the clouds. also as David as said, get a good hdri background. You can also compose against a good background in postpro.
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Samo
 
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Re: Exterior Rendering

Post Thu May 04, 2017 8:12 am

Take this image. The selected area and the histogram of that area tell us the difference between a material lit by sun+sky versus only the sky, which is about 2/5 of the histogram. This is about 2.5 EV stops in a camera light meter. Any material with similar properties (fully diffuse, rought and opaque) will behave in a similar way, for instance stone or plasted walls. That's why you can use a clay render to set up the lighting ratio. But then in that image the digital camera is not using a linear but a S-type tonemapping curve to encode the image, therefore you should use a similar curve in the Blender editor and in real time, when you set up your lighting rig.
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Samo
 
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Re: Exterior Rendering

Post Thu May 04, 2017 9:09 am

Samo wrote:Take this image. The selected area and the histogram of that area tell us the difference between a material lit by sun+sky versus only the sky, which is about 2/5 of the histogram. This is about 2.5 EV stops in a camera light meter. Any material with similar properties (rought and opaque) will behave in a similar way, for instance stone or plasted walls. That's why you can use a clay render to set up the lighting ratio. But then in that image the digital camera is not using a linear but a S-type tonemapping curve to encode the image, therefore you should use a similar curve in the Blender editor and in real time, when you set up your lighting rig.


Interesting! Can you explain more? do you make a render and compare the histogram to the background image to see if the curves are similar?
surena
 
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Re: Exterior Rendering

Post Thu May 04, 2017 9:21 am

Indeed. I adjust sky power and then sky+sun power against clay render passes, looking for similar ratios than the photo of reference. It is very important then that we work with a photo of reference and that the renders are correctly tonemapped in every lighting step, not only on final result. It is also very important than you land whites in the correct area of the histogram. Most of this stuff is explained in the grey 18 workflow tutorial. I usually compose in post production against a good background using masks.
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