Release: wom_archlight 1.0 - physically accurate light shader

[SimFox]

Hi SimFox,

It is a pure mental ray shader, so it should certainly be possible to make it work in Max. The only reason I have not done so is that I was under the impression that Max’s built-in photometric light already does most of what wom_archlight can do, so I figured there would be little demand.

If there is demand for it, I am happy to port to Max though.

Well, in some part yes but it is this line in the description that got me salavating:

A shader to create object/geometry lights

I assume it isn’t simple FG/self-illumination setup is it?

It would be really great if you could port it to 64bit Max. Would it be version dependent? I mean the version of MR is different in every max…

[wombat778]

Well, in some part yes but it is this line in the description that got me salavating:

A shader to create object/geometry lights

I assume it isn’t simple FG/self-illumination setup is it?

It would be really great if you could port it to 64bit Max. Would it be version dependent? I mean the version of MR is different in every max…

Ahh, I see. No, it is a proper object/geometry light, not a simple self-illumination.

I don’t see any reason why I could not port the light object shader to Max quite easily. I will see what I can do.

In terms of versions, I don’t think it would make much difference what MR version you use. Mental ray started supporting object lights in version 3.1, and I think that ever since Max started using MR it has used more recent versions than that.

[fabergambis]

I’m not sure if this is what you meant, but the following code will hook up a single light shader to multiple lights. You could make it into a shelf button or something.

{
 // select all the lightShapes in the hypershade, then select the wom_archlight, then run this...
 string $sel[] = `ls -sl`;
 
 for($n=0; $n<size($sel)-1; $n++) {
 	connectAttr -f ($sel[size($sel)] + ".message") ($sel[$n] + ".miLightShader");
 }
 }

– David

David, I want simply to tell you THAAAAAAAAAAAAAAAAAAAAAAAANKSSSSSSSSSSSSSSSS!!!
You’re GREAT! :bowdown:
You can’t imagine how long I need a script like this.

[JayHoo]

Could it be that the “scene unit size” does not really work in the wom_archlight?

I create a scene with a simple plane and a sphere. Mia_material_x with no reflection (similar to lambert). One area light over the scene with the wom_archlight.

The sphere is 7cm high and the area light is 30cm over the ground plane.

I used the photographic lens shader. “Physically correct” is activated in wom_light.

Inside the wom_archlight I set intensity to 58 (stands for a 60W light bulb), unit of intesity is Candela.

Scens Unit Size is both set to “centimeter”.

Now when I render the rendering is black. When I set the unit size to “milimeter” the rendering looks ok. When I change the unit size in the maya settings, nothing happens.

The problem is that now I couldnot set up a scene where I get an illumination which is similar to an light bulb .

[ytsejam1976]

It’s strange, JayHoo. I don’t have never problem to set in millimeter or centimenters or meters.
Can you post the scene?

[JayHoo]

Ok, I got what I want. In the photographic lens shader I had to use the “arbitrary mode” (Film Iso = 0).

Sorry to blaming this great shader. :sad:

Now i can put an area light 2 meters over my plane and had a reasonable lighting.

I looked up the values for a 100W bulb and compared it with Candela and Watt settings for them. And it is 99.9% the same. Really great. :wip:

[wombat778]

Ok, I got what I want. In the photographic lens shader I had to use the “arbitrary mode” (Film Iso = 0).

Sorry to blaming this great shader. :sad:

Now i can put an area light 2 meters over my plane and had a reasonable lighting.

I looked up the values for a 100W bulb and compared it with Candela and Watt settings for them. And it is 99.9% the same. Really great. :wip:

Hi Jayhoo,

Actually, I think you should stick with the non-arbitrary mode if possible (e.g, set the film ISO to something like 100) and the cm2 factor set to 1.

When you were having the problem, what did you have the camera settings set at? I know that Maya by default will set the ISO to 100, shutter to 1/100 and f-stop at 16. Those are WAY too high for an indoor photograph, and would result in a black image with a real camera. My camera exposure meter is telling me that without a flash for an indoor night shot to use ISO = 100, shutter = 1/5, and f-stop of 2.8. That is in a room lit by 3 75-watt bulbs, so the image will probably still be too dark for a single 60-watt bulb. Anyhow, try those settings and see if you get something closer to correct.

[JayHoo]

thanks for your quick reply Wombat.

The advantage of the arbitrary mode towards the photographic mode (how the non-arbitrary is called) is that i only need to set ISO = 0. In the other mode I had to use the three values and I am not used to that photographic stuff.

The result with the arbitrary mode looks quit convincing. To get the same in photo mode I set ISO to 90 and shutter, f-stop to 1.

Scene Setting: plane, sphere and an area light 2,5 meter above.

Intensity = 58 Candela (this is like a 60W bulb)

[wombat778]

thanks for your quick reply Wombat.

 The advantage of the arbitrary mode towards the photographic mode (how the non-arbitrary is called) is that i only need to set ISO = 0. In the other mode I had to use the three values and I am not used to that photographic stuff.

Fair enough, if you aren't used to camera settings then arbitrary mode may be fine.  The advantage of using the photographic mode is that even if you do not know the settings, you can get a real life camera to do the work for you by just taking a picture in a room with approximately the same light level, then inputting the settings the camera chooses directly into mia_exposure_photographic.  

Anyhow, it does not surprise me that you had to use ISO 90, shutter 1 and fstop 1 to get a decent image.  In real life, ISO 90 film is quite slow and would generally be used for outdoor shots (ISO 400 is probably more realistic).  Also a single 60 watt bulb in a room is not very bright, especially if you are only relying on direct light (e.g., not using FG/GI).

[JayHoo]

When I use ISO 400, shutter 1 and f-stop 2.8 then it looks good too.

If I knew the cam settings from the setting that would be nice too. But without the arbitray mode is easier to set up.

[marlaS]

Hi wombat,
thank you very much, your shader is very very very good! :applause:

I read about soft shadow and point light, you say it isn’t possible…
…so I tried… and tried… and I remember my test (made with my friends ystejam and fabergambis a century ago… :wip: hhe) with the mib.photometric and I found a solution!:

connect your wonderful shader to the slot color of the point light (yes the pointlightshape1)

… and it works! Now you can set up the light radius, soft rays in the maya pointlightshape node but remember to raise the ray.depht.limit in order to get the same result of your traditional workflow.
I know this method need testing, but for now it work very well

Thank you again!

[ytsejam1976]

Ehy alessandro. I want to see your fansworth House with womArchLight.

:buttrock:

[SimFox]

Ahh, I see. No, it is a proper object/geometry light, not a simple self-illumination.

I don’t see any reason why I could not port the light object shader to Max quite easily. I will see what I can do.

In terms of versions, I don’t think it would make much difference what MR version you use. Mental ray started supporting object lights in version 3.1, and I think that ever since Max started using MR it has used more recent versions than that.

:bowdown:

please, please, please!

everyone using max would be soooo grateful for this miracle!

[ytsejam1976]

I’m search to use this on max and :

API  0.0  error  301181: .\shaders_standard\include/wom_archlight.mi, line 6: bad default value type integer, parameter "colormode" expected boolean
API  0.0  error  301181: .\shaders_standard\include/wom_archlight.mi, line 11: bad default value type integer, parameter "intensitymode" expected boolean

I 'think taht a GUI or other. And i attached on light on 3dsmax, but some strange, no great control for mow and the light profile not appear, or the wom light profile on 3dsmax not work. But i think that wombat resolve all.

[tuuhia]

Hi wombat,
thank you very much, your shader is very very very good! :applause:

I read about soft shadow and point light, you say it isn’t possible…
…so I tried… and tried… and I remember my test (made with my friends ystejam and fabergambis a century ago… :wip: hhe) with the mib.photometric and I found a solution!:

connect your wonderful shader to the slot color of the point light (yes the pointlightshape1)

… and it works! Now you can set up the light radius, soft rays in the maya pointlightshape node but remember to raise the ray.depht.limit in order to get the same result of your traditional workflow.
I know this method need testing, but for now it work very well

Thank you again!

interesting solution…thank you for the info

[wizlon]

Hi wombat,
thank you very much, your shader is very very very good! :applause:

I read about soft shadow and point light, you say it isn’t possible…
…so I tried… and tried… and I remember my test (made with my friends ystejam and fabergambis a century ago… :wip: hhe) with the mib.photometric and I found a solution!:

connect your wonderful shader to the slot color of the point light (yes the pointlightshape1)

… and it works! Now you can set up the light radius, soft rays in the maya pointlightshape node but remember to raise the ray.depht.limit in order to get the same result of your traditional workflow.
I know this method need testing, but for now it work very well

Thank you again!

From my tests using this technique, you also have to set Shadow Factor to 1.000 under wom_archlight Advanced Tab.

[marlaS]

From my tests using this technique, you also have to set Shadow Factor to 1.000 under wom_archlight Advanced Tab.

Thank you for the tip, I will test it!

[wombat778]

All,

I have updated wom_archlight to version 1.2. Here is the changelog:

Version 1.2 New Features/Changes
[ul]
[li]Added visible area light falloff options[/li][li]Default visible area light intensity now is related to light output[/li][li]Added ability to use spotlight manipulator in softimage[/li][li]Added a Relative Inner Cone Angle mode that operates similarly to the Spread parameter of Softimage’s soft_light[/li][li]Cosine distribution is now physically correct when using lumens/watts in most cases[/li][li]The default distribution mode is now Reference Light mode[/li][li]Added an Enable Attenuation checkbox to enable attenuation[/li][li]A few minor performance enhancements[/li][li]Internal code reorganization and cleanup. Now only one function handles all unit conversions[/li][/ul]Version 1.2 Bug Fixes
[ul]
[li]Fixed bug where visible area intensity would not affect reflections[/li][li]Fixed bug where dark light colors could make intensity inaccurate[/li][li]Fixed bug causing artifacts when using lux/watts/m2 at spotlight focus[/li][li]Fixed some AETemplate logic bugs for Maya version[/li][li]Fixed bug that could cause white dots under certain circumstances[/li][li]Other minor bug fixes[/li][/ul]Since some people had trouble with the megaupload link, I am sticking to highend3d this time. Here is the link: http://www.highend3d.com/maya/downloads/shaders/wom-archlight-5849.html

As always, please let me know if you run into trouble!

[fabergambis]

Wombat, I have no words to say to thank you for your effort on sharing and developing this unbelievable light shader. Really thank you.
SInce you released the first beta, I’m using this shader for testing and refining old projects with artificial lights: that’s what I was waiting for…

[ytsejam1976]

Wombat, I have no words to say to thank you for your effort on sharing and developing this unbelievable light shader. Really thank you.

quote all

:buttrock: