How to Make an Interior Brighter

[mrkwlkn99]

Hey everyone, I'm a newbie and have watched as many lighting tutorials as I possibly could on YouTube, and yet I am still having trouble lighting my entire room to make it look like it's natural, and it's daytime.

Here is a thread of some interiors:
https://forum.keyshot.com/index.php?topic=22309.0

And mainly something like this one is what I want to do:
https://forum.keyshot.com/index.php?action=dlattach;topic=22309.0;attach=57295

How is that room so well lit up? The walls, the ceiling, everything is so well lit. Are there hidden IES lights or Area lights everywhere? Is it done in post-production? Am I missing something obvious? In the image, it looks like the poster has all the "lights" in the room turned off, and yet the entire room is well-lit and looks like day time. How is something like this done?

I find my rooms are always incredibly dark unless I am adding windows everywhere and area lights behind them blasting in light. In my attached image I have a plane behind the windows at 100,000 lumens, and the room is completely dark.

[Niko Planke]

Hello mrkwlkn99,

My expertise on this purely technical, i rarely get to render interiors myself, but here are some things you can check.
If you use window panes (e.g. glass sheets) i would start out with making sure caustics are enabled, that can cause rooms with such a setup to look to dark(you can also try to hide the panes to verify them being the cause).
Along the same lines i suggest to make sure you have a sufficiently high amount of Global illumination bounces(usually 6-12 should be sufficient but depending on your scene you may need more)
It also looks like your  walls and ground are fairly dark, using brighter materials should also help a little.
I would also assume that you can get some additional brightness by adjusting the exposure in the image settings.

If all the above does not help your best chance might as you already assume to add hidden area lights.

[RRIS]

Excellent tips by Niko. I would use the area lights more as an alternative to HDR environments and use a strong spotlight as the sun. Keep in mind the sun can be up to 120,000 lux for a bright day, so don't be afraid of high output values.
Enabling caustics and putting glass in the windows might be overkill, if you want to speed things up, you can remove the glass and use area lights and disable the cast shadows for them. That way they let through the sunlight and block the view of the dark expanse outside the house

[KristofDeHulsters]

I render interiors quite often, combine the following the have full control:
1. Put Planes covering the entire size of the window just outside of it. Apply area light with the desires ambient color. You can crank these numbers up quite high. Set these to not be visible to the camera in the Area Light setting (so they cast light but don't show as geometry).
2. Don't use Solid glass with Caustics (it is harder on your machine), use the Basic Glass preset.
3. Right behind the light planes have another plane with emissive material. Apply any texture to it that you want your outside view to be.
4. If you want hard shadows outlining what is in the room. Either add a spotlight/pointlight outside of the windows and crank up those numbers really high. Alternatively you can add a very small but bright pin to the HDRI.
5. Adjust the brightness of the planes in step 1 until your light is close to what you like it to be.
6. Do final adjustments using the exposure and gamma setting.

When you're rendering in interior mode, the default ray bounces should be fine. You don't need to tweak anything there.