.:: Indigo 0.9T5 and Exit Portal -- second part

[OnoSendai]

The rule is, if you use exit portals, you should cover all openings to the outside.

[Kram1032]

Oh, I see....
he didn't cover one opening...

[mrCarnivore]

but how is "outside" actually defined? and what about meshlights? do meshlights pass through exit portals? they don't because they are meshes and meshes are ignored, right? So for meshlights the exit portal just acts as a black mesh and meshlights that are sending light from other directions still contribute to the image?

[tizxx]

Hello boys.

I undestand that exit-portal we must use inside a room and all openings or apertures (if we want to use exit-portal) must be filled by exit portal too

The normal of plane that define the exit-portal must be directed to inside the room.

When we use exit portal no geometry will be rendered out side the exit-portal too. Only sky-light and probably HDRI enviroment (I'm not just tested)

When we use exit-portal is usefull use BIDIRECTIONAL = true and others mode = false

if we use METROPOLIS and/or HYBRID without BIDIRECTIONAL we have indesiderated renderings...

---


thank you to all
and thanks again to Nicholas.

[CTZn]

but how is "outside" actually defined?

I guess that's the volume where the camera is not...

[mrCarnivore]

but how is "outside" actually defined?

I guess that's the volume where the camera is not...

exit portals have nothing to do with volumes afaik...

EDIT: corrected the quotes

[Kram1032]

I guess that's the

room

where the camera is not...

[mrCarnivore]

How is a "room" defined then? and what about a "room" with open sides? and what about meshlights? in which cases are they inside the "room" and in which cases outside?

[Kram1032]

Close any hole in the outermost walls. you know, what's a hole in reality.

[mrCarnivore]

That doesn't answer any of my questions. All this exit portals stuff is way to fuzzy for me. Can anyone please give be exact advice?

Does the exit portal only effect the sunlight and only sunlight that passes through the exit portal has any effect on the scene? Doesn't seem correct, because cou can render the outise of a room sealed with walls and exit-portals just fine. theexit portals just act as walls themselves...

So how does it work? and how are meshlight effected by exit-portals?

[Kram1032]

an exitportal is like a vacuum cleaner but for light.
It forces all the rays, coming through it. that's why non-Exitportal spots get black (in the BiDir variant) - I've no idea, why they stay visible, in the no-BiDir variant.

Everything behind the Portal gets invisible, as no light hits the geometry.

That's how I explain myself the current Exitportal. - However, there are better Portals, that don't make the outer eometry invisible, but I've no clue, how they work.

An exitportal has only one direction, so you need to check the normal.



Does this finally help you?

[mrCarnivore]

No it doesn't help one bit. I know just as much as I did before. According to your description, meshlights inside the room would be invisible because the light doesn't pass through the exit portal. Also what about meshlights outside the room? and what if there is no room?

[BbB]

This is getting philosophical... I know wonder whether anything at all has genuine existence if it does not get hit by a light ray. Oh well...

[Kram1032]

meshlights are meshes, so they're geometry, which means, they're invisible, if outside an exitportal - slowly you're coming to questions, I can answer you^^

If there's no room, everything is black, where there is an exitportal, at least in BiDir mode.

Without BiDir, everything should be visible, according to the tests, tizxx did.
Not shure, though.
I guess, the only two differences, without bidir in an outdoorscene, are:
1) geometry is hidden, behind the portal
2) the position of the portal clears up faster.


And before you ask:
You should make sure, a hole's COMPLETELY covered, but don't make the portal too big: the efficiency of it gets lost, then (as it simply forces light to pass it) Light'd hit unseen stuff, that never comes to the camera...
(Same outdoor, which makes them completely useless, there)

[mrCarnivore]

@BbB: That sounded very philosophical, indeed. What I meant was, what if there is no rom, but just the stuff in the room there.

@Kram: Thx for trying to help me, but there are still not all the questions aswered...

How does the exit-portal work? Does ALL light have to go through there to be visible or just the sunlight? Even if it's just the sunlight, how can the outside of the room be visible, when the light clearly does not go through an exit-portal as seen in the examples? Any when sunlight does not have to go through a portal, why is the opening not covered by an exit portal black? That's where the question comes: What is _inside_ a room and what is _outside_. This is especially interesting, when there is no closed room, but a partially open one.

Or did I confuse some things and sunlight actually _has_ to go through an exit portal and is otherwise invisible and meshlights don't?

Also I modelled a room with windows covered with an exit portal and an open roof. The Meshlight way above the room cold still light it, even though the light was not going through an exit portal. So do meshlights just interact with exit portals as if they were some kind of other object (thus the meshlights are not visible through the exit portal but still can light stuff whether or not through a portal)?