The ceiling light PBR cheat

WendyLuvsCatz

I thought I might share the obvious

if you have lights on the ceiling rather than make them emitters in iray, Octane or Luxrender and presumably Cycles, why not put holes in the mesh either via geometry editing or transmaps and stick the sun above and make it big!

no fireflies!!!!!

you still get an "indoor light" look as confined to those fittings,

alternatively if not showing the ceiling at all, just hide it.

I am only posting this as some may have overlooked the obvious, we are working with filmsets/ a photography studio after all, the real thing they would add lights have cut out sets etc.

Oso3D

I think 'mess with stuff in geometry editor' is one of those second or third stage things DS users really ought to explore.

It's WAY easier than I had feared, and it can do some great stuff. I particularly like the ability to create new surfaces/material zones.

 

WendyLuvsCatz

Something I have been doing in Carrara for years and years  and in studio once we all got the pro version free with the extra tools.

AFAIK was not in DS3 but I only had advanced of that.

TabascoJack

timmins.william said:

I think 'mess with stuff in geometry editor' is one of those second or third stage things DS users really ought to explore.

It's WAY easier than I had feared, and it can do some great stuff. I particularly like the ability to create new surfaces/material zones.

 

 

I agree!  Being able to create new surfaces for materials is really easy and results in the ability to do some really cool stuff.

Richard Haseltine

But the sun is highly directional while emitters would emit over a wider range.

tl155180

Plus, if I recall correctly... if you try to light a geometric interior room with sunlight coming from outside (ie the dome) then Iray will take considerably longer to render the scene than it would with, say, photometric spotlights or flat plane mesh lights on the ceiling instead.

Thats always been my experience anyway.

Petercat

Doing it like that would be like having a skylight, imagine a nice, warm bright spot on the floor where the cat would sleep. Making the surface emissive (a plug forDZfire's Real Lights) would spread the light more evenly around the room. You could even make flourescent tubes out of primitives and make them emissive: http://cat-man-dancing.deviantart.com/art/Cheap-and-easy-iray-DAZ-lighting-tutorial-589098114

I make most of my iray lights out of Maclean's Everyday Morphing Primitives: www.daz3d.com/everyday-morphin…
and DZfire's Real Lights: www.daz3d.com/real-lights-for-…

Richard Haseltine

Don't forget that you can give the iray lights a geometry, which may well be faster than an emissive surface.

WendyLuvsCatz

I will admit I have used this more in Octane where the sun size can be very big creating softer shadows

Scavenger

I'm not sure how this helps with rendering.

Scavenger

timmins.william said:

I think 'mess with stuff in geometry editor' is one of those second or third stage things DS users really ought to explore.

It's WAY easier than I had feared, and it can do some great stuff. I particularly like the ability to create new surfaces/material zones.

 

It CAN be way easier...depending on how the original model was set up.  Or it can be a HUGE flat pocket bread that takes hours til you just give up.

tl155180

Richard Haseltine said:

Don't forget that you can give the iray lights a geometry, which may well be faster than an emissive surface.

On the downside though they can't be hidden in a scene, whereas emissive surfaces can be set to opacity 0.0001 and will not be seen but will still produce the light.

mjc1016

tl155180 said:

Richard Haseltine said:

Don't forget that you can give the iray lights a geometry, which may well be faster than an emissive surface.

On the downside though they can't be hidden in a scene, whereas emissive surfaces can be set to opacity 0.0001 and will not be seen but will still produce the light.

Taht sort of is good/bad depending on what you want to do.

If you absolutely can't have the emitter visible, then sacrificing some speed for invisibility is worth it.  But if you can live with visible emitters or move them off-camera, then it's probably not worth using the slower methods.

tl155180

mjc1016 said:

tl155180 said:

Richard Haseltine said:

Don't forget that you can give the iray lights a geometry, which may well be faster than an emissive surface.

On the downside though they can't be hidden in a scene, whereas emissive surfaces can be set to opacity 0.0001 and will not be seen but will still produce the light.

Taht sort of is good/bad depending on what you want to do.

If you absolutely can't have the emitter visible, then sacrificing some speed for invisibility is worth it.  But if you can live with visible emitters or move them off-camera, then it's probably not worth using the slower methods.

I don't actually find emitters slower to render than the photometrics. If anything they seem to be a bit faster but that might be because I tend to use flat plane emitters which are very quick.

If I stick an emitter on a blub or a 3D shaped object, then yeah its slower. But I wouldn't want to hide those in the scene anyway

Oso3D

What becomes a problem is something like 'this lamp bulb is part of this lamp object. I'm going to make it an emitter, aren't I so clever!' (time passes) 'hmm, this lamp is looking a little chunky, better add Subdivision. ... Hey, why is my render suddenly crawling?'

(I'm pretty sure I've gone through the above at least three times, literally like that)

 

Tobor

tl155180 said:

Richard Haseltine said:

Don't forget that you can give the iray lights a geometry, which may well be faster than an emissive surface.

On the downside though they can't be hidden in a scene, whereas emissive surfaces can be set to opacity 0.0001 and will not be seen but will still produce the light.

There is a setting for hiding the emitter for direct view in the render

If you ever want to fully explore Iray's canvas feature and make use of the various kinds of render passes available you'll eventually hit a brick wall if you use any kind of emission surface. Some canvas types must be rendered in Interactive mode, and here, the emission surface has no scene lighting effect. Building all your lighting solutions around emissive objects will eventually fail you.

Unless all your renders are similar and fairly routine, it's best not to get too used to anything in Iray. There are pros and cons to all of the lighting techniques.

evilded777

Tobor said:

tl155180 said:

Richard Haseltine said:

Don't forget that you can give the iray lights a geometry, which may well be faster than an emissive surface.

On the downside though they can't be hidden in a scene, whereas emissive surfaces can be set to opacity 0.0001 and will not be seen but will still produce the light.

There is a setting for hiding the emitter for direct view in the render

If you ever want to fully explore Iray's canvas feature and make use of the various kinds of render passes available you'll eventually hit a brick wall if you use any kind of emission surface. Some canvas types must be rendered in Interactive mode, and here, the emission surface has no scene lighting effect. Building all your lighting solutions around emissive objects will eventually fail you.

Unless all your renders are similar and fairly routine, it's best not to get too used to anything in Iray. There are pros and cons to all of the lighting techniques.

Thanks for that. Learned something.

mjc1016

The difference between a single poly plane and photometric light averages about 1 sec, at least with the tests I've done.  But once you start making more polys per surface the difference climbs, slowly at first...but before you know it, there is a significant one.

WendyLuvsCatz

So are you all suggesting making part of the ceiling an emitter surface  or placing an emitter plane on the ceiling can be as fast and noise free as just using the sunlight? 

I do animations and basically am looking for ways to render frames as quickly and noise free as possible so use cycloramas, backdrops, open sets etc where I can, I cut out walls ceilings etc simply as unlike other render engines in physically based ones you cannot use recieve shadow only etc settings likewise on skydomes etc.

I was thinking also for a "sun" in a closed skydome if a geometry light would work as well as sky and dome, as HDRi etc you cannot pan and dolly in a scene as it stays still in relation to the set unlike a sky-dome or skybox.

Tobor

If your renders don't show the ceiling, and it's otherwise a uni-mesh where you cannot easily move, remove, or hide it, another option is the Iray sectioning plane. It's in the Create menu. The plane will "slice" though geometry, allowing anything on one side to be literally chopped off in the scene. The light from an HDRi or sun can now come through.

The sectioning plane is a little hard to use because you can't easily see it in preview. I've found switching to the Front view helps in adjusting its elevation. You can also tilt the plane and cut off just a portion of a ceiling/wall, or a wall.

Obviously, the best interiors are those designed like movie sets, where the walls and ceilings are movable/removable. In my content library I have marked those with a ! to move them to the top of the list. There are quite a number of sets that I've purchased over the years that are too much of a hassle to use in Iray, so I've just dumped them. Not enough time in the day to mess with their limitations.

tl155180

Tobor said:

tl155180 said:

Richard Haseltine said:

Don't forget that you can give the iray lights a geometry, which may well be faster than an emissive surface.

On the downside though they can't be hidden in a scene, whereas emissive surfaces can be set to opacity 0.0001 and will not be seen but will still produce the light.

There is a setting for hiding the emitter for direct view in the render

If you ever want to fully explore Iray's canvas feature and make use of the various kinds of render passes available you'll eventually hit a brick wall if you use any kind of emission surface. Some canvas types must be rendered in Interactive mode, and here, the emission surface has no scene lighting effect. Building all your lighting solutions around emissive objects will eventually fail you.

Unless all your renders are similar and fairly routine, it's best not to get too used to anything in Iray. There are pros and cons to all of the lighting techniques.

Yeah, I have tried using that setting to hide the emitter with the photometric spotlights etc but it doesn't seem to do a very good job of it, especially when it comes to reflections in windows and mirrors etc. Even with the emitter set to not appear I still see a big black shape reflected in windows from where the spotlight is positioned. You don't get that with low opacity emissive planes. Personally though I prefer the more natural look that emissive surfaces give (when used as hidden scene lights) anyway. I do like to use spotlights for specular highlights as well, but I do most of my main lighting work with emissive planes and my customers seem to like it too. I guess some people might say my renders all have a very similar look but it sells, so my motto is if it ain't broke don't fix it.

tl155180

fool said:

So are you all suggesting making part of the ceiling an emitter surface  or placing an emitter plane on the ceiling can be as fast and noise free as just using the sunlight? 

I do animations and basically am looking for ways to render frames as quickly and noise free as possible so use cycloramas, backdrops, open sets etc where I can, I cut out walls ceilings etc simply as unlike other render engines in physically based ones you cannot use recieve shadow only etc settings likewise on skydomes etc.

I was thinking also for a "sun" in a closed skydome if a geometry light would work as well as sky and dome, as HDRi etc you cannot pan and dolly in a scene as it stays still in relation to the set unlike a sky-dome or skybox.

Speaking from my own personal experiences I'd say that using a flat plane (just create a standard plane primitive) as an emissive surface with the Iray Emissive shader and putting it just below the ceiling, pointed downwards, is a great way to light a room and its very quick and easy to render. Even better is using a few emissive planes. However, if you cut the whole ceiling off the room and used the sun as a light then that would also be pretty quick to render - although the light would be way more directional and wouldn't disperse as well.

You'll start running into longer render times if you try to cut a section out of the ceiling (like a skylight) and just use the sun to light the room through that section because then it has to fill in all the areas that are not directly hit by the sunlight with only reflected light alone. In my experience this takes a lot longer to render.

For example, I did a scene with the set Aftermath http://www.daz3d.com/aftermath and wanted to light it using just the sun-sky settings. I did a few images that way and found that I had to add in some spotlights because although the areas hit by the sunlight were well lit, the other areas were almost pitch black because the walls of the structure were blocking out most of the environmental light from the dome. So I decided to get rid of the sun and stuck a huge flat emissive plane over the set instead which did a much better job of lighting the environment more evenly. The downside of that is that you don't get a very strong light / shadow contrast or any real directional light. So I had to add in some spotlights again. The second method rendered much quicker though.

It basically just comes down to what look you're trying to achieve.