A quick test I made these 3 last days.
We often found tutorials and trials showing us how to achieve photo-realistic renders, but rarely based on real photos. We can have a feeling of what is realistic, but when we compare to a real photographed object, we see many other things. Subtle color variations, shadows running darker in some spaces, reflections of light.
I thing Blender do a good job making basic environment lightning, but we need to adjust things to really get closer to real lightning.
Being photorealistic means often being flat, or common like. Reality is not so amazing sometimes. In cinema we often see CGI that pops out the screen, make itself really beautiful and shiny, but its not like reality. The artist and film makers needs to make something that’s stands out. Some rare exception occurs, like the effects in Neil Blomkamp’s movies, like “District 9”. They are incredible. The aliens not seems CGI. The same in “Elysium”. The robots looks real props on set. That is being photo realistic, because it don’t try to be more that reality. It don’t try to be self aware, like: “Hey look at me I’m a great effect, many people works hard on it, we want to be seen”. Beautiful yes, but it feels not real, so we don’t rely on it.
Last tries I add realism by adding area lights where more reflections (radiosity) needed. But now I try the compositing option.
It can be painstakingly long to adjust it all inside Blender, and takes hours of rendering when we have multiple lights and so on. Compositing gives more freedom to finetune the result, and the difference between a good (or even spectacular) rendering and a realistic one is by finetuning. I’m sure many of you knows that. But to get that, we must observe real pictures of similar object in similar surroundings.
Here I replicate a photo I took some years ago.
Hours of job: around 3 hrs modeling, 6 hrs finetuning, 1 h compositing. No texturing, except for the sky, I avoid this to be focused on light and shadows. I add a small amount of noise in the white walls in compositing.
The modelling is not accurate, I didn’t wanted to spend too much time on this.
– And the photograph:
It still really not perfect. Some shadow parts (around windows) are still too bright, and some variations are missing in the balconies area. Down a render before compositing:
The Blender scene setup:
In this case I still added some area lamps where the render lack some bouncing light, near surface receiving direct sun.
But the main real-like effect comes with compositing. There is many areas where a color temperature change, some parts are darker or lighter in many ways. Without looking closely to a photo, I cannot imagine or invent where to change these details.
The render passes that helps me the most: Ambient Occlusion (to darken concave areas) and Glossy Indirect (to lighten where light is bouncing). The walls are a mix of diffuse but mostly glossy material, with large roughness. Glossy materials looks better that diffuse one, but render longer and makes some fireflies.
And some details to focus on:
In photography, we enhance contrasts in different parts of the image. That’s make the picture looks closer to reality. Means selecting some shadow parts, some others bright parts and adjust curves. It’s almost the same job here.
A night time variation (this time, no photo to look upon, I just try to build a mood of a building far from street lights, to see some stars):
And a fog day: