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Unwanted Reflections From Primitive Light Emitters

PrestonArtworksPrestonArtworks Posts: 14
in New Users

I use primitive light emitters such as planes and cylinders for lighting individual characters, as they give a nice even lighting (a bit like photographers studio soft boxes), and they work great for scenes with no background / backdrops. But when I do include props behind the character I often get problems with unwanted reflections on the background props coming from the light emitters. I try to position my lights in ways that minimise reflections, but sometimes I am unable to eliminate unwanted reflectios completely.

Are there any ways I can control unwanted reflections within Daz Studio (the preferred option), or essentially, do I need to render eg, character and background, separately and then put them together in an image editor?

Thanks in advance for any suggestions.

Comments

  • felisfelis Posts: 5,720

    You cannot directly control reflections, but you can increase roughness of the background objects, and lower glossiness, to make it dimmer.

  • PrestonArtworksPrestonArtworks Posts: 14

    Thank you, I just tried your suggestions and they worked perfectly! Was able to increase and improve lighting on the foreground character, while reducing the reflection (actually, hard to see it at all) on the background prop.

    I note your comment about not being able to fully control reflections, but if these simple settings work as good on other renders, I will be quite happy!!

    Thanks again.

  • felisfelis Posts: 5,720
    edited November 11

    What I meant by not being able to fully control it, I meant that there is no setting for telling an object to not be affected by these lights. But you can change surface settings of objects like you did.

    And good it worked smiley

    Post edited by felis on
  • PrestonArtworksPrestonArtworks Posts: 14

    I did wonder if there might be a setting that could switch on / off reflections for individual objects in a scene, but its useful to know thats not possible, and happy with what I have learnt today from this!

  • barbultbarbult Posts: 26,156

    You can prevent your emissive primitive from being visible in reflections, by setting the advanced properties Iray Visible to Primary Rays and Ghost Light Factor on your emissive primitive. You don't need to change the background objects. 

    https://www.daz3d.com/forums/discussion/609556/creating-a-ghost-light-daz-studio-4-21-1-26

     

  • PrestonArtworksPrestonArtworks Posts: 14

    @Barbult, the info on your link looks a bit 'advanced' for a newbie Daz user like me, but I have book marked it for future reference and will try to get my head around it if the need arises. In the meantime, I am happy to drag a couple of sliders using the example mentioned above!! Thanks for the link though, appreciate your help.

  • barbultbarbult Posts: 26,156

    PrestonArtworks said:

    @Barbult, the info on your link looks a bit 'advanced' for a newbie Daz user like me, but I have book marked it for future reference and will try to get my head around it if the need arises. In the meantime, I am happy to drag a couple of sliders using the example mentioned above!! Thanks for the link though, appreciate your help.

    That linked info is written by Rob, on of the Daz Studio software developers. He writes very technically, to be precise and accurate. It is sometimes difficult for users to understand how to apply what he describes. You can find more tutorial-like instructions, but I didn't have a handy link to that. I wanted you to know that it IS possible to implement what you wanted to do.

  • barbultbarbult Posts: 26,156
    edited November 12

    @PrestonArtworks Here's an AI summary that is pretty good. It omits the critical step of setting emission on the object that will be your ghost light, but you already have that step mastered.

    Well, I edited this about 10 times trying to fix the the text. It shows up correctly in the editor but fails when posted. I finally pasted it into Notepad++ and copied it back out as plain text. Hopefully it is legible now.

    In Daz Studio with Iray, a "ghost light" is created by setting the "Iray Visible to Primary Rays" property to Off in the Parameters pane for the object you want to use as an invisible light source. 

    The general process for creating a ghost light and managing its visibility involves:

        Select the geometry (e.g., a primitive plane or sphere) that you want to act as your light source.

        Run the "Create Advanced Iray Node Properties" script found in Content Library > Default Resources.

        In the dialog box, check the options for both "Iray Visible to Primary Rays" and "Iray Ghost Light Factor" and click "Accept".

        In the Parameters pane (under Display > Rendering > Iray), locate the newly added properties.

        Set "Iray Visible to Primary Rays" to Off.

        Set "Iray Ghost Light Factor" to a value greater than 1.0

     

    Post edited by barbult on
  • PrestonArtworksPrestonArtworks Posts: 14
    edited November 12

    @barbult, thanks for providing the 'user friendly' version of the instructions, and I can confirm it worked smiley. I created a simple scene with a character and background prop, with lighting from a cylinder. The lighting on the character was fine and there were no reflections from the cylinder on the background prop. Have saved the file for future reference re settings, but have also bookmarked this page to save your simplified instructions.

    Thanks again for your support yes.

    Edit to add: I realise now I have actually used this script previously (some months ago) but had not fully understood its purpose, I thought its only purpose was to hide light souces in the camera view that were not wanted in the final render. What I didn't realise was that it also hides reflections caused by the light source on other nearby objects - the whole purpose of this post!

    Post edited by PrestonArtworks on
  • barbultbarbult Posts: 26,156

    PrestonArtworks said:

    @barbult, thanks for providing the 'user friendly' version of the instructions, and I can confirm it worked smiley. I created a simple scene with a character and background prop, with lighting from a cylinder. The lighting on the character was fine and there were no reflections from the cylinder on the background prop. Have saved the file for future reference re settings, but have also bookmarked this page to save your simplified instructions.

    Thanks again for your support yes.

    Edit to add: I realise now I have actually used this script previously (some months ago) but had not fully understood its purpose, I thought its only purpose was to hide light souces in the camera view that were not wanted in the final render. What I didn't realise was that it also hides reflections caused by the light source on other nearby objects - the whole purpose of this post!

    The script has many options, and in combination, they make even more options. It can be hard to figure out, for sure. I hope it helps achieve your goal.

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