I have a question to solve a problem for a project.

I Have a dark room (without interior lights) with more than one window, I need to enlighten with external light but without direct sunlight is in the room.

only a reflection of external light as strong as a solar day.

I attach a picture to explain better ....

ideas?

thanks

What you are wanting (as I understand it) is Northlight (light from the north sky).

The simplist way I can think of to do it is to use BB's dome, and turn up the illumination coming from it to about 300-500%. Make sure the walls and ceiling of the room ARE casting shadows. 

I'm sure there is a more sophisticated way to do it, but this works for me in this situation.

Thanks but doesen't work.... there is no shadows from outside....

i'm thinking about a light emitter object outside....

Since there's no direct light, there'll be no hard shadows, but there will be accurate soft shadows.

This kind of lighting requires pretty aggressive render settings - note that I've disabled the Irradiance Cache - and it looks like the test render will take hours.

I'll post the results when I can.

I'd be interested in the solution to this as well, looking forward to seeing how your render turns out and the length of time it took.

Looks like there's a geometry issue to the right of the middle window.

Right, I'm gonna crank up HDR's V value to 12 (1200% intensity) and leave it to run overnight.

that looks cool!!!  I gotta try this out :)

Even with generous Irradiance Cacheing, IDL artifacts are apparent: the way to render scenes lit this way is definitely with the cacheing off.

this will make it even slower, but to reduce IDL blotches, change IDL IC to 100 (no cache, just to agree with cspear), increase IDL samples to 4096 (or higher) and increase IDL bounces to 16 (or higher).  the latter also allows for decrease in hsv value of hdri. these values must be set in the numeric entry fields, as the d3d sliders maxx out too low. of course, some of these can't be set properly in the default poser render settings dialog box.

ray-trace IC setting is ignored by FFRender when using IDL IC, but nocache is less prone to errors and is reproducible, unlike cache, which is "monte carlo".  nocache reduces blotch size, but samples tend to eliminate blotches.