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Hiding Iray lights in DAZ Studio

GKDantasGKDantas Posts: 200
in Technical Help (nuts n bolts)

Hi people, I am creating a new set of lights for DS (no more HDRI), but sometimes I need to hide the object that is emitting light, but when I do that the light simple dont work. Any ideia how to hide the light object without tuening it off?

Comments

  • SzarkSzark Posts: 10,634

    I beleive the trick is to set Opatcity (Cutout) to 0.001 or 0.01, can't remember which, and crank up the intensity. 

  • ToborTobor Posts: 2,300

    What kind of lights? Szark's commentsw apply to emissive objects. The value to use is more like 0.0001 -- the minimum. You usually don't need to increase the luminance value to compensate.

    For regular lights such as spotlights that have an emitter larger than a point, you can choose to Hide Emitter. This only works in "dfirect view" -- when the light is viewed directly from the camera. You will still see the light emitter in reflections and through semi-transparent objects, such as smoke or fog.

     

  • GKDantasGKDantas Posts: 200

    Hi Tobor, its for emissive objects, but looks thats a big diference in shadows and intensity. I am doing some render tests right now. Will post them later

  • GKDantasGKDantas Posts: 200

    Very visible... need to find another way

    CutOut-001-X-200-porcento.jpg
    1040 x 650 - 100K
  • ToborTobor Posts: 2,300

    What is the exact Cutout Opacity and :Luminance settings you are using?

  • GKDantasGKDantas Posts: 200

    Cutout 0.001 and the same Luminance value, only double the Luminous Efficacy, using Watts for the light.

    cutout.png
    425 x 357 - 26K
  • glaseyeglaseye Posts: 1,311
    edited March 2017

    The lowest value I could enter for opacity is 0.0000001

    Gave the result in the attached images . value 1 and value 0.0000001

     

     

    1.0000000.jpg
    600 x 600 - 91K
    0.0000001.jpg
    600 x 600 - 86K
    Post edited by glaseye on
  • GKDantasGKDantas Posts: 200

    What settings do you use in the light?

  • glaseyeglaseye Posts: 1,311

    This ones

     

    0.0000001-settings.jpg
    311 x 529 - 39K
  • ToborTobor Posts: 2,300

    So what are we looking at here? The images in your posts three up look the same. Did you change any parameters between them, or not?

    A cutout value of 0.0001 is fine, which is the minimum value you can still see in the dial readout. 

     

  • glaseyeglaseye Posts: 1,311

    Same settings except for the opacity. The cube is the meshlight, not visible in the second render. The headlamp of the camera was set to off on both renders. Environment 'scene only' so no other light sources. I've used this setting more when using a (veeery distant and strong) meshlight to emulate sun light when using my skydome.

     

  • ToborTobor Posts: 2,300

    glaseye, sorry ... my bad. I didn't scroll back to the top to see you weren't the OP.  Your demonstration shows the luminace is not affected by the cutout value, as long as that value is > 0. However, highlights and reflections are affected, as I discussed here back in Sept 2015.:

    http://www.daz3d.com/forums/discussion/62526/quick-howto-making-mesh-lights-invisible-to-the-camera

    Of course, that was for D|S 4.8. I haven't repeated my tests since then, so I don't know if the latest 4.9 versions behave differently.

     

  • GKDantasGKDantas Posts: 200

    Looks theres a problem with the emission when you resize the light source...

    luz-normal.jpg
    1600 x 2000 - 484K
  • ToborTobor Posts: 2,300
    GKDantas said:

    Looks theres a problem with the emission when you resize the light source...

    And Iray would be working incorrectly if it didn't behaves this way. The output choice you specified is in watts for the entire surface. Enlarge the surface, and the light is spread out to a larger area. That makes it appear dimmer. A doubling of the size means the light incident on any area of the scene is just 1/4 of what it was. The same thing happens in the real world.

    Instead of watts, which is more useful for point sources, you may wish to choose an area output, such as cd/cm2, which is candles per square centimeter. This has the advantage of being in centimeters, which is D|S default unit of measure, plus giving you the ability to use more human numbers -- a luminosity of 100 is quite high. That would be 100 lumens for each square centimeter.

    The light the emissive surface produces is the same no matter what units of measure you select. What changes is the value you adjust. So pick the one you feel is best for your workflow, but be prepared to make adjustments to fit.

  • GKDantasGKDantas Posts: 200
    Tobor said:
    GKDantas said:

    Looks theres a problem with the emission when you resize the light source...

    And Iray would be working incorrectly if it didn't behaves this way. The output choice you specified is in watts for the entire surface. Enlarge the surface, and the light is spread out to a larger area. That makes it appear dimmer. A doubling of the size means the light incident on any area of the scene is just 1/4 of what it was. The same thing happens in the real world.

    Instead of watts, which is more useful for point sources, you may wish to choose an area output, such as cd/cm2, which is candles per square centimeter. This has the advantage of being in centimeters, which is D|S default unit of measure, plus giving you the ability to use more human numbers -- a luminosity of 100 is quite high. That would be 100 lumens for each square centimeter.

    The light the emissive surface produces is the same no matter what units of measure you select. What changes is the value you adjust. So pick the one you feel is best for your workflow, but be prepared to make adjustments to fit.

    Hi Tobor, I understand the problem with Watss, but if you look at bottom images one is the source without Cutout opacity and the other is the same scene with 0.0001 Cutout value, look how the like is less bright them the example in the top with no resize in the light source. Maybe a bug?

  • ToborTobor Posts: 2,300

    I don't know your settings. Looks like you accidentally turned off cutout opacity all the way, which will turn the light off. Look at glaseye's examples. This is how it works for me as well.

     

  • GKDantasGKDantas Posts: 200
    Tobor said:

    I don't know your settings. Looks like you accidentally turned off cutout opacity all the way, which will turn the light off. Look at glaseye's examples. This is how it works for me as well.

     

    I will check that

  • FirePro9FirePro9 Posts: 456

    I believe you can use Iray Canvases to choose what items in your scene will render, without impacting the lighting or reflections.

  • GKDantasGKDantas Posts: 200
    FirePro9 said:

    I believe you can use Iray Canvases to choose what items in your scene will render, without impacting the lighting or reflections.

    Never used this before...

  • FirePro9FirePro9 Posts: 456

    Here is a good quick tut on Iray Canvases:

    http://snowsultan.deviantart.com/art/Iray-Canvas-Tutorial-565641976

     

  • GKDantasGKDantas Posts: 200

    Thanks

  • bwise1701bwise1701 Posts: 247

    So I tried the Canvas approach and when I edited the node list I unchecked all the mesh lights - in the render I see the same effect as before - the mesh lights still render - at least I can see the one whose cutout opacity is one reflected in a window...

    Is there some other trick I'm missing here?

  • FirePro9FirePro9 Posts: 456

    Reflections I believe render accurately, as if the object were not hidden from the reflection.

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