I'd been having all sorts of problems trying to use IDL for indoor scenes where the room only had a smallish window. Previous threads spoke of compensating for Poser's lack of camera settings (aperture and exposure settings) by cranking up the lighting. I tried that, but it was always too dark.

Anyway, I got to thinking about using a genuine SLR camera to photograph the room in my scene, and what setting I might use. If I was to use 100 ASA film with a nominal aperture of f4 or so, I'd expect an outdoor shot in full sunlight to have an exposure time of about 1/60th to 1/125th of a second. Using those same settings in a room like that in my scene, I'd expect the exposure time to be about 1 to 2 seconds.

Applying that rule of thumb, and knowing that every increase in the time roughly doubles the amount of light, I counted up the steps (1/60, 1/30, 1/15, 1/8, 1/4, 1/2, 1... 7 steps) then doubled the light the same amount: 100, 200, 400, 800, 1600, 3200, 6400. That's right, set the light of the sun to %6400!

Then the skydome. Same counting, set ambient to match. Ambient to 64!

I rendered it, and it worked! A but dull still, but within expectations. I 'bracketed' one stop up (light to 10,000, ambient to 128), and got the image above...

Basically it means I can apply general rules for a camera to estimate values for light in IDL. Still not as good a result I might expect if there were genuine exposure controls in Firefly, but a big improvement over what I'd been getting.

Hope this is of use to someone!

Oh, forgot to mention: 3000 samples, 6 bounces, 32 minute render time.

Quote - Oh, and I recall reading that Poser 'clips' ambient values

It never did. There is plenty of disinformation in the forums.

there's like dimples in the corner edge where the walls meet.

piersyf,

can you post up a pic of your skydome material settings?

When I do this the image on the skydome just blows out to white.

can you post up your render settings as well?

you can also incr. IDL bounces to 16 or 32 and see if it helps.  may be a tad slow, but also might avoid envsphere blowout, if not using HSVTM.

there's no shadows or bright squares from the window grid pattern on the floor or anything.

the concept is -
to light the inside of a room with only an outside light source?

If the sun isn't shining directly in the window, there would barely be any even if it's very bright outside. The light is too diffuse to cast very strong shadows.

The attached image is taken from two photos I just took with my cell phone. The one with the obvious shadows is taken from my office, that has the sun shining directly in. The second is from an office that faces east, so the sun is not shining directly in right now. You'll note that you can barely make out the shadows of the window blinds, and it only because the wall where the shadow falls on is right next to the window. A little further away, you wouldn't be able to make them out at all with that exposure.

The envirosphere WILL be blown out with the correct "exposure" settings. In a photograph lit entirely from natural light coming through a window, it's going to be be a very bright window indeed, if it's not completely white. The OP's discovery makes perfect sense to me.

The only way to get a nice outdoor view and a lit indoor is to do exactly what architectural photographers do: cheat.

If you've ever seen a photographer working on architectural shots, you'd think they were about to do a fashion shoot. Same set of big lights, reflectors, etc -- all to give the impression of natural light. :)

You can see the blowout in the image I put up: to show the interior clearly, outside the window is massively overexposed.

Quote - If you've ever seen a photographer working on architectural shots, you'd think they were about to do a fashion shoot. Same set of big lights, reflectors, etc -- all to give the impression of natural light. :)

This is a problem if we're looking to emulate a photograph using Firefly. Camera's have very limited exposure ranges so they have to reduce the contrast by elevating the lower range with artifical lighting or use HDR. I don't know what Poser's Firefly engine effective EV range but it must have one.

Sorry guys, was teaching at a country school today, so just got back (3 hour drive each way).

As several of you have already said, the skydome will blow out to white at these exposure levels, but so does a real photograph.And yes, the concept is to light a largish room only using external lighting with IDL.

The image I posted has no light on the floor or walls because the sun is behind the camera (over your virtual right shoulder). The image is using JUST the environmental light (from outside). I should also state that there is a window behind the camera, and the window you CAN see in the image is only half of the actual window (you can see a bit of the other half in the very bottom left of the window frame).

This isn't a 'discovery' as such; BB for one has mentioned raising light and ambient levels to compensate. My realisation was the point of comparison to roughly equate Poser light to real light and 100 ASA film. That gave me a benchmark to calculate an approximation as to what settings I'd need to get the results I'd expect. Having said that, if I were to try to emulate architectural imagery I'd have to do the same as they do; use internal lighting (mesh or otherwise) to fill the room inside, raising the amount of light hitting the virtual film. That means I don't need as long an exposure, so the external lights can be wound back to adjust. Eventually that would stop 'blowing out' the skydome.

The main issue is the artifacts along geometry seams. It looks like throwing that much light at the walls (which have genuine mesh thickness) is still letting some leak through. That's why I think having Firefly with camera type settings (focal length and apperture) would give better results. You could just set the lights to 100%, ambient to 1, and adjust from the renderer, and (hopefully) not get those artifacts. Even at 5000 samples, IC at 25% and 12 bounces I still get blotchiness. Not too difficult to correct in Photoshop, but I'd like to not have to.

light-leak artifacts at wall seams may be obviated with thicker wall slabs, but eliminating splotches need either point fill light inside room (fast) or not using irradiance caching (slow).

they haven't said much about adding exposure time/ASA to FFRender yet.

Quote - This is a problem if we're looking to emulate a photograph using Firefly. Camera's have very limited exposure ranges so they have to reduce the contrast by elevating the lower range with artifical lighting or use HDR. I don't know what Poser's Firefly engine effective EV range but it must have one.

Check "HDRI optimized output", save the image as .HDR or .EXR and the dynamic range is, for all pracitcal purposes, unlimited. You can then take that .HDR/.EXR into a capable image editing program and adjust the exposure to how you like, it, apply tone curves, compress highlights, or treat it like you would treat an HDR created by a digital camera and multiple exposures.

(edit: http://http.developer.nvidia.com/GPUGems/gpugems_ch26.html says "A range of one-million to one is 20 stops in photographic terms." and that OpenEXR's floating point representation "is a dynamic range of a trillion to one.").

One option to dealing with a very wide EV range in Poser could be to render to a 32-bit image, either HDR or EXR (IIRC turn off tone mapping, enable HDRI optimised output and set gamma to 1 in the render settings).

Then you have to use a third-party app to tone map the resulting file to display or print it - I've used both Photoshop and Photomatix Pro, though I know there are a number of others too.

edit - oops, cross posted :)

Using HDR renders can still give you artifacts, just as using multiple exposures and combining them for a true HDI photograph does. The software to process them is good, but it still depends on the limitations of the camera, and most digital cameras are still grainy as hell in the lower exposure ranges. Renders aren't, but you get different results when you process the HDRIs.

I render to HDR for the same reason that I always shoot in RAW format -- because, well, more data to work with is usually preferable to less, so why not? But if you adjust the exposure of a single image too much out of its natural range, you will get glowing shadows and so on.

I have not tried to use Photomatix or Photoshop to combine several renders with different light settings, though. 

--

I got tired of the corner splotches I got from light emitters and IDL in Poser. I now use fill lights. (BB gave out a set of fabulous IBL's with VSS a long while ago, and they're the best IBL's I've ever used. On a low intensity, they're very good). For me, the main advantage of fill lights is not only the elimination of most blotches, but the ability to get a semi-decent render at much, much lower quality render settings.

However, if you're aiming for ACCURACY, fill lights may not be the answer.

Hi there

As above I would add at least one point light above the ceiling or I would use Infinite light,rendering enclosed space as is interior is bit pain with Poser,you still can get splotchess

Here are my renders which I've rendered with Poser Pro 2014 and IDL,,in this renders I've used above D3D Firefly settings and light setup consist from 2 infinite lights(One acting as sun with 42% and one without the shadows set at 40%),1 IBL(Light have set intensity at 30%) and 4 ceiling lights(Point light set as inverse and intensity 5%),Gamma Correction OFF and Sphere from Bagginsbill and HDR picture from HDRlab and TrueForm Contemporary Bedroom

Thanks,Jura

jura, if you delete all IBL and limit to IDL / fill lite, I daresay shadow occlusion shall improve.  PP2014 and later.

Quote - jura, if you delete all IBL and limit to IDL / fill lite, I daresay shadow occlusion shall improve.  PP2014 and later.

Hi there

I'm not usig AO or I don't have enabled AO on any lights,I'm using IBL only due with IBL light not why,but lights are bit brighter,on IBL light is not attached any image(HDR or EXR,JPG),only colour is bit blue

Thanks,Jura

Miss Nancy never said AO. Occlusion is the word to describe objects blocking ambient light. We have to use that word even when we're not talking about the Poser feature that implements it called Ambient Occlusion (AO).

Occlusion is something that happens with IDL, too, and if it is missing then IDL looks wrong. You added so much shadowless fill light that your image doesn't look realistic anymore. It's missing the right amount of occlusion.

Miss Nancy makes a suggestion to improve your render appearance, and it has nothing to do with AO.

Adding too much fill light kills the ambience. I understand why you're doing it - to stop the splotchies. But it's too much.

Quote - Miss Nancy never said AO. Occlusion is the word to describe objects blocking ambient light. We have to use that word even when we're not talking about the Poser feature that implements it called Ambient Occlusion (AO).

Occlusion is something that happens with IDL, too, and if it is missing then IDL looks wrong. You added so much shadowless fill light that your image doesn't look realistic anymore. It's missing the right amount of occlusion.

Miss Nancy makes a suggestion to improve your render appearance, and it has nothing to do with AO.

Adding too much fill light kills the ambience. I understand why you're doing it - to stop the splotchies. But it's too much.

Hi BB

Sorry I've misunderstood Miss Nancy wording,agree I've added too much of shadowless light

In those two last renders I've deleted all lights and I've used only Infinite light acted as sun with shadows with intensity set at 42%,one extra Infinite with 40% acted as like fill light ?

Thanks,Jura

Oh that's SOOOOO much better. 

As nice as Jura's renders are, I have no concerns over lighting modern fishbowls. Before I made the connection to film, the scene above may have taken 3 or 4 renders, fiddling with lighting levels, to get something nice. This took 2; one calculation render, one adjustment render, because I now have a method/workflow to indicate where the changes need to be made.

In this case I imagined the drop in exposure time pointing the lens out the window, then to the right at the wall, and guessed 2 stops. I then had to cheat a bit to compenstae for the fact that our eyes adjust to the light level of what we are looking at, whereas cameras can average the light in an image.

2 stops means the sunlight is 400%, but I made the ambient 3 instead of 4 so that you can still see detail in the sky. To compensate for the lower light, and to 'average' the light levels inside, I parented a point light to the camera 4 inches/ 10cm above the viewpoint (Y axis), set it to 15% and set the colour of the light to match the blue in the sky (should have been the colour of the walls, probably), and turned off shadows. IDL intensity 0.7, 5 bounces, 2000 samples.

Rendering using HDR settings to adjust brightness in postwork won't work, because lowering the light levels brings on bigger blotches in the original image, and those just get brighter too.

Of course, removing IC would help, but then I'd have to endure stupid render times. AT least this is a quick fix in postwork (much quicker than than waiting for a perfect render). Depends on how much time you have, I guess.

Quote -  removing IC would help

It has been quite a long while since I tried that. So I did it last night. What a surprise - I disabled IC, and Poser Pro 2014 completely lost its marbles trying to render it. It did numerous things wrong. I've never seen this before. And, of course, it took all night.

The env sphere HDR value was set to 16. (I'm not in a fish bowl - with the relatively small angular cross section of these windows, I needed four stops.)

After two hours I got the usual ridiculous light leaks and splotchies. But, at least the lighting looks about right.

The texture map for the floor is now everywhere. Even the pawns, which are not UV mapped at all, are projecting the texture map. ???????

I see little evidence of "lighting" calculations now - it's all a uniform super bright.

I'm mystified. What happened to IDL without IC? Did they completely break it or what? Anybody else see this behavior?

Note: The walls and ceiling are boxed, while the floor is just one-sided. Obviously the floor is receiving back light from the sphere underneath. I don't know why - my recollection was that back-side lighting was ignored unless the material had scatter or translucence set on it or normals forward checked. This has neither.

your beautiful marble floor ...

Quote - Here was the first render, with what I thought were very aggressive render settings. I used the D3D Render Firefly dialog where I can control things directly. I had IDL bounces=6, samples at 6000, Irradiance Cache set to 90.

The env sphere HDR value was set to 16. (I'm not in a fish bowl - with the relatively small angular cross section of these windows, I needed four stops.)

After two hours I got the usual ridiculous light leaks and splotchies. But, at least the lighting looks about right.

Hi BB

I've question where are you adjusting/setting HDR Value ?

You are adjusting Ambient value or on the HSV ?

Thanks,Jura

Quote - You are adjusting Ambient value or on the HSV ?

HSV and plugged into Alternate_Diffuse, but what difference would that make? If plugged into Ambient_Color and Ambient_Value used to adjust brightness, the math is the same.

I use the HSV because it is handy for saturation adjustments as well. But if I'm not touching Saturation then it makes no difference.

was SR4 responsible for snafu in re: IDL with no IC?  it used to work so well (albeit slow).  I didn't update to SR4, hence will try it w/unmod version.

Quote - > Quote - You are adjusting Ambient value or on the HSV ?

HSV and plugged into Alternate_Diffuse, but what difference would that make? If plugged into Ambient_Color and Ambient_Value used to adjust brightness, the math is the same.

I use the HSV because it is handy for saturation adjustments as well. But if I'm not touching Saturation then it makes no difference.

OK got it and thanks for reply 

Here is latest render,I've used only HDR and yours EnvSphere,no lights at all,HSV set at 8.0(although I didn't touched colour etc ),rendered with GC on via D3D Firefly,bounces 6,6000 samples 

Thanks,Jura

Nice render, Jura. You shouldn't need to mess with colour if you are lighting with HDR, as the colours are taken from the image. I haven't been using HDR, just a jpg on a skydome and using Poser infinites, and they seem to look better if you sample either the skydome jpg (blue) or the floor/walls material.

Just to restate/clarify my original reason for posting, it was the discovery/realisation that Poser/Firefly behaves similary to film. To put that another way, to achieve what might be considered a linear progression in tone requires an exponential progression in both light and ambient. BB stated that he used 'aggresive' settings, but my realisation is that they are not aggressive, but appropriate.

The sun is behind the camera. If the sun is due south, the window faces due east. No direct light on the window at all.

This was with the single infinite set at 100% and the skydome (non HDR) set at an ambient level of 1.

Blotches were still an issue. The renders took about 13 minutes each at 3000 samples and an IC of 50.

This last image at 3200% and ambient of 32 was at 10,000 samples, and an IC of 99 and took 2 hours 16 minutes.

Oh, forgot to mention; all were 4 bounces.

Hmmm. Looking at the tone scale image, it's pretty obvious that each lower level is twice as well lit as the level above it, so the scale progression is properly described as exponential. However, I think we get so used to seeing these scales that we THINK of them in a linear fashion, and so applied lighting increments linearly. At least, that's the excuse I'm going to stick with.

Screenshots of render settings and camera settings would be helpful for those of us who are following the discussion.

If you know of a camera setting that impacts on the brightness of an image, please let me know. It's what I am hoping Poser will add to Firefly in the future. Are you saying it already has that capability?

Ah, I misunderstood. You were talking about F-stops, so I thought you had changed something on your main camera. So are you doing a HDR lit only testing or are you using a Poser light (like an inf)? Doesn't sound like it though. Environment sphere settings then?

The last series of images (the greyscale types) are single light (infinite), colour is white, strength is as listed, varying from 100% to 6400%.

Skydome is normal, non HDR image, just a jpg on a dome, and ambient values are the only thing that changes, from a value of 1 to a value of 64, as listed in the scaled image.

They are the ONLY light sources in the images.

The talk about f stops is because I am equating Poser to an old SLR camera, and how with the real thing, moving up a stop doubles the amount of light hitting the film, and so is an exponential progression, and hence this test to see that in fact it DOES work the same way in Poser/Firefly.

I hope SM does eventually put exposure options into the camera settings within Poser.

There is no standard to this, just as there isn't with a normal camera. Each situation will be different. The last image I posted worked at 3200% and ambient of 32 for the skydome, but the first image I posted at the very beginning of the thread was too dark at a light setting of 6400% and ambient on the skydome of 64.

This was all about saying, if you have used an SLR camera, that this approach will get you to a ballpark approximation of good lighting more accurately and more quickly than just guessing, which is what I had been doing until now.

To correct a previous comment of mine; BB said aggressive RENDER settings, not aggressive lighting settings.

My bad.

Quote - Nice render, Jura. You shouldn't need to mess with colour if you are lighting with HDR, as the colours are taken from the image. I haven't been using HDR, just a jpg on a skydome and using Poser infinites, and they seem to look better if you sample either the skydome jpg (blue) or the floor/walls material.

Just to restate/clarify my original reason for posting, it was the discovery/realisation that Poser/Firefly behaves similary to film. To put that another way, to achieve what might be considered a linear progression in tone requires an exponential progression in both light and ambient. BB stated that he used 'aggresive' settings, but my realisation is that they are not aggressive, but appropriate.

Hi there

I'm not touching the colour only value and yes I've used too JPG,really depends on the scene

Not sure I've tried to touch the Ambient value,but this doesn't make any difference if deflaut colour is set to black,if you will change this to blue or white yes will make difference 

Agressive render setting,as above I'm usign only 6 IDL bounces,6000 samples as max,but usually 1200  samples is enough for fully lighted scene with IDL bounces 2-4

But I can see,you are using GC(Gamma Correction),in my case I'm not using too much GC,I prefer render with GC off,but thanks for examples and help guys,at least I'm not alone with those splotchess issues 

Thanks,Jura

Further to BB's discovery that turning IC off gets crazy results, I tried a render with IC at 99.5% (so not exactly 'off'), and it was crazy too. At 99% it works fine.

thanks for discussion of exposure vs. IDL brightness, piers. they can use this later when adding said feature.  I have to confirm BB's findings in re: unchecking IC, using BBcornelltypebox.pz3 posted either here or on his site.  we're now limited to add fill light to lessen splotches.

   apparently all versions of PP2014 (SR4 or earlier) will fail similarly.

You're welcome, Miss Nancy. I didn't think the conversation would get to this level, finding something broken in PP2014, but now maybe they'll fix this issue in Firefly in future releases.

I seem to be finding an upper limit too... at 51,200% and ambient 512 (8 second exposure) fill lights can't compete with the ambient levels, so even at 10,000 samples and IC at 99, fill lights still leave (very small) blotches. To completely remove the blothes the fill light needs to be at such a level that the whole thing is washed out.

By that stage, the render times are as long as it would be using Luxrender.

I would like too thanks as Miss Nancy for this thread piersyf,really appreciated for this,I've several issues with IDL splotches,which I always have in some scenes,but really appreciated for this thread 

Thanks,Jura

Quote - thanks for discussion of exposure vs. IDL brightness, piers. they can use this later when adding said feature.  I have to confirm BB's findings in re: unchecking IC, using BBcornelltypebox.pz3 posted either here or on his site.  we're now limited to add fill light to lessen splotches.

   apparently all versions of PP2014 (SR4 or earlier) will fail similarly.

New ray accelerator?

Poser9 = ray accelerator "kd tree"

Poser 10 = ray accelerator "EMBREE"

Has anyone logged this bug yet with SmithMicro?