How to light interior scenes naturally?
amyw12
Posts: 63
Hi,
I am wondering, how do you light interior scenes naturally? For what I mean, I have attached a few photos to my post (all rights go to respective owners).
I like this natural, sunshine coming in through the windows look and a lack of artificial indoor lighting.
Are people relying on bright HDRIs for this? Or HDRI combined with other lighting? When I try doing this the whole room is dark and only some light comes in from windows. I have no idea how to achieve this effect.
Any advice appreciated. Thank you so much.
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Comments
Two places to start, both in render settings (assuming you have a decently sunny HDRI or are using sun/sky settings for the light). Under Tone Mapping, lower the exposure value. Something in the 11 or even down to the 9 range. That's usually where I start, and often enough to get decent indoor lighting, though that still often means long renders to avoid noise. Additionally, under the environment tab, you can increase Environment intensity. I usually don't raise that more than about 5, but if the window or wherever the light comes in isn't visible in the frame, you can get away with making that brighter without washing it out completely.
You can also work with adding light sources out of frame, or ghost lights that won't be visible in the render. I prefer to start with the other options first though to see if that is enough to get realistic results.
One thing that is used a lot but rarely discussed is the iray section plane (do a web search for details); it is a flat plane or collection of planes that "slice" through content such as walls and makes everything invisible on one side. Imagine if you had a closed room sliced so it is now like an open box that lets the light flow in, combine that with a photo hdri to generate natural light, a photo flat plane to provide outside scenery, and spot lights through the windows to provide realistic shadows... and loads of rendering time....
You don't get near enough light bounces in the scene to light an interior realistically; how it is configured is not even enough for a night time scene with cloudy skies, no moon, and a single 60 watt bulb in a small room at 10'x15'x8'.
Just rotate your sun/sky or HDRi to point at the windows if you want it that way, Turn ON the Architectural filter if the windows aren't too big and lower the exposure value until you get enough brightness. That's all.
How what is configured? Iray, by default, allows paths to bounce until they run out.
My advice would be use Sun-Sky in the render settings and rotate until the sun is coming through the windows. Set the time to around 4-5pm. Any later and the light begins to darken, any sooner and the sun is too high in the sky to stream nicely into the room.
I would also place a ghost light across the whole of the main window(s), and set the emission on this high, and another ghost light on the ceiling, but with a much lower emission value. These lights should significantly reduce the render time, without making that big a difference to the lighting effect, as most of the light will still be coming from the windows via either the sun, or the window ghost light.
In addition to what others have said, and in general, I find that interior surfaces (I'm talking about the material parameters) need to reflect much more light than they currently do. Unfortunately, this leads to much longer render times and much more noise.
- Greg
The original default, I think its of -1. Maybe the actual problem is CPU rendering and not allowing my renders to run for 10s of 1000s of iterations. Sorry!
-1 means as long as needed, no cap.
Exterior "Sun sky only" with some ghostlights in the room to give a basic level of lighting where the sunlight shining through the windows doesn't get to. Kinda what @Havos already wrote above.
With proper placement and luminance values for the ghostlights you can get about every lighting you would ever want..
Where is a good source to learn about this architectural filter?
Most interior scene have a mix of indoor light fixtures and outdoor "sunlight" streaming in through a window. Iray makes the process easy to setup. Every light source should emit light. Rather than using a HDRI, a plane emitter outside the window can shine "daylight" (color temperature) into the scene exactly where and at the angle you want. It give the most flexibility.
Here:
https://www.migenius.com/doc/realityserver/4.3/resources/general/iray/manual/index.html#/concept/architectural_sampler.html
Thank you all so much for the amazing advice. Can't wait to give it a try the next time I have the chance.