[ababak]

A modifier that could be applied to an object that represents a room (typically, just a box with holes in place of windows). That modifier will tell the engine that everything that is outside that object is irrelevant and only light rays that come inside that object really matter. That will help to make indoor scenes while using outdoor-shot HDR or Maxwell Sky for lighting without the speed penalty or ugly workarounds.

What do you think?

[dariolanza]

Hello Andrey,

In fact, in a situation like the one you are describing (the camera inside a closed room with open windows and only the environment outside) everything out of that room does is already considered irrelevant for the algorithm, and the whole empty space is not sampled at all.
The rays casted from the camera and bouncing around the room reach the window holes and impact the environment, informing the engine about the color and intensity of the light in that specific direction. In that situation, anything else is irrelevant on the whole empty space, and the algorithm is really well optimized to do so.

Let me know if this helps to clarify your question.

Greetings

Dario Lanza

[ababak]

Hello Dario,

Thank you for an explanation. From what I read on these forums and in the lighting tips I thought that was the case. So it looks like now there is no way to overcome that "large amount of indirect bounced light" problem without adding invisible emitters here and there.

From the designer's point of view it looks like a place for some automation, as these hacks are so easily algorithmized: place the emitters at each window pointing inwards to reinforce the light entering through that window, match their colour and intensity, make them invisible and so on.

Is there something in the development (something that you can talk about ) that will improve the optimisation of interior renders in the future?

Thank you.

[dariolanza]

Hello Andrey,

Well, reinforcing the exterior lighting with invisible emitters and make it look nice is more like an artisan trick that needs a considerable amount of artistry, photographer eye and good taste, so it hardly can be automated by any feature.

It is like what a photographer does to set screens and lamps hidden here and there on a photograph: you can point to some generic rules, but there are just an orientation. The photographers has to adapt them to each specific case, changing the position, size, color and number of lights depending on each situation (color of the furniture, mood, intention, desired look, intensity of the natural light, presence of actual artificial lamps enabled in the scene, etc...) watching from the camera viewfinder.

So is it almost impossible to create any automatic setup for those situations, and the tweaking that any automatic generic system may need to fit a particular situation would involve even more time than the needed to place the emitters from scratch.

However, I wouldn't be difficult to code an script on your 3D host platform that may place instances of a given emitter plane object, set them to invisible, assign an emitting material, etc. I'm sure it could be done easily on your platform by coding some lines.

Greetings

Dario Lanza

[ababak]

Hello Dario,

Thank you. I understand your point, artistic light or special mood will always stay. But the photographer has a simple option of using longer exposure and getting a realistic noise-free picture without using additional lights. I remember the history of Maxwell Render and there were times when something could be done only by using some hacks, but sooner or later there followed a new version and boom — it became a new killer feature (R2, layers, displacement, SSS, grass, light trails, volumetrics, custom sun radius and so on) that could be used without special tricks. Maybe one day we will use an outdoor HDR for interior lighting without thinking about using additional emitters.

[eric nixon]

Using hdr to light an indoor scene only makes sense if the hdr is just a clear sky, in which case maxwell sky will give a cleaner result. Personally I'm getting great results with just a skydome using a gradient and a huge dark plane to represent the ground.

[ababak]

Hi Eric,

Looks very nice, thanks for sharing!