Dumb question time: Turn an existing object into an area light?



  • @ghostship I can't tell, honestly. It's too dark and too grainy to come to any conclusion.

    And the light bulbs just look stupid - not at all realistic.



  • The one problem I see is that unless it's night outside, the light coming in through the window is very weak and diffused. Walls, floors and ceilings will also reflect the light in a room.



  • Another massive problem with using the ambient light type - no control over the light falloff model!


  • Poser Ambassadors

    This Superfly prop is two-piece; place the mount base against the ceiling, then select the lamp and Y-translate it up/down to fit the scene.

    Superfly lightcaster lamp

    In the Superfly render settings, set mesh light samples to 15. Use a couple of subsurface samples for the shade.

    Here is the material for the lamp bulb, a soft pink light. Adjust strength of lightcasting by lightening or darkening the color box indicated. Light grey will give modest boost; dark grey will cast strong light. The lampshade can be separately adjusted, but it should respond to the mesh light.
    0_1479854726543_demo lamp bulb mat.PNG

    For your situation, with a modest number of lamps, I recommend using both a point light within the bulb and the mesh light technique; just make the point light weaker and lessen the mesh light boost (lighten the color box). The combination looks better than either method used alone.
    Be forewarned that the more you must rely on meshlighting, the more mesh light samples -and therefore more render time- will be needed.

    For scenes with a lot of lights (Atlantis, Lothlorien) use only the mesh lighting.

    P.S. The light falloff for a mesh light will be inverse square.



  • Keep in mind that Superfly is a reverse path tracer. The render engine needs to find light on as many ray casts as possible.

    I would add a plane to it, just outside the window. Set it to be invisible, and turn up the ambient so the engine finds light from that source.
    There are two advantages to this, you can select the color light you want, and the amount cast.

    You can do the same thing with the lamps as well. Set the ambient on the bulb where the bulb looks right, then do a lightpath setup on the shade where it casts light without blowing it out. You end up with far more light being cast, without blowing things out.

    Here is a very simple Poser scene to demo a hidden emitter. 0_1479855313113_hidden emitter.zip.txt Rename and extract.

    As far as controlling the fall off rate of these lights, that can easily be done in any scene with a cube and a volume absorption node.


  • Poser Ambassadors

    Oh, more user info...

    Adjust the brightness of the lamp itself with the root node's ambient_value.

    That color block in the bulb material is for adjusting the ratio of apparent brightness to lightcasting strength.

    For light coming in through the windows, I have lightcaster materials for the P11 "construct" skydome.

    P11 construct material sampler


  • Poser Ambassadors

    Rough render test, mesh light only for the lamp (no point light inside).
    0_1479857830398_demo lamp rough test.png



  • @seachnasaigh

    Interesting solution!
    Till now, I was using a mat setting created by Bagginsbill with two spots by lamp, to avoid the too luminous point below the lamp.
    Furthermore, I cannot set the mesh light samples as I render most of the time with the GPU.
    With two spots per lamp + one big area lamp near the ceiling, oriented towards the ground, to control the overall light of the room, that gives this:

    alt text

    In case someone is interested in BB's lamp shade setup:
    alt text
    Downloadable here.



  • @matb said in Dumb question time: Turn an existing object into an area light?:

    Another massive problem with using the ambient light type - no control over the light falloff model!

    If I'm not mistaken, mesh lights have inverse square falloff.



  • Well, I am getting there. Thank you seachnasaigh, and all the others for the help.

    I still have some of this wrong, but I am learning.........but, seach, I can't figure out what node to plug in to create "boost adjust dark-light." I'm lost there, can't find the node that would give me that.

    0_1479863499982_EZDomeInteriorSuperfly2.jpg


  • Poser Ambassadors

    Oh, that's just a simple color node. I renamed it to make it easier to understand.

    You could just copy the materials from my prop to the corresponding material zones of the set you're using.



  • @ghostship said in Dumb question time: Turn an existing object into an area light?:

    @matb said in Dumb question time: Turn an existing object into an area light?:

    Another massive problem with using the ambient light type - no control over the light falloff model!

    If I'm not mistaken, mesh lights have inverse square falloff.

    Yes, I suspected that from looking at some test renders, but they don't seem to have an identical falloff to a point light of the same intensity in the same location.



  • @seachnasaigh said in Dumb question time: Turn an existing object into an area light?:

    Oh, that's just a simple color node. I renamed it to make it easier to understand.

    You could just copy the materials from my prop to the corresponding material zones of the set you're using.

    Thanks! I know I could do it the easy way (copy) but I really want to learn this and I'm one of those people who has to DO it to understand.



  • @Glitterati3D said in Dumb question time: Turn an existing object into an area light?:

    Well, I am getting there. Thank you seachnasaigh, and all the others for the help.

    I really like the feel of this scene but I wonder if it would be better served by a level of transparency on those shades? And I think somebody else mentioned that there is not enough light spill from the window.
    BTW, did you know that your hivewire link does not work?



  • @matb It's still a work in progress...........I'm learning something I really want to know and haven't taken the time to get through.

    Here's the latest render where I have made some nice headway on the ceiling light, the lamp next and then I'll play with exterior lighting.

    0_1479870222741_EZDomeInteriorSuperfly2.jpg

    Oh, and the Hivewire link works for me, but I wouldn't be surprised if it was an "illegal" link off the forum. We never did get official word about external links.



  • @Glitterati3D said in Dumb question time: Turn an existing object into an area light?:

    Oh, and the Hivewire link works for me, but I wouldn't be surprised if it was an "illegal" link off the forum. We never did get official word about external links.

    Looking nice, tranquil. Oddly the Hivewire link is working for me too now.



  • Caveat: I don't use mesh lights much at all. Mainly because their strength is dependent on the proportion of geometry they have in the scene, so unless you have calculated the surface area of the emitting object, you are left with guessing as to the lighting contribution it provides.

    To comment on this scene I've made a stack of assumptions;

    1. that the coffee table is the point of focus for lighting
    2. that the day outside is overcast
    3. that the light overhead is around a 75w equivalent and about 0.8m from the table surface
    4. that the table lamp to the side is a 40w equivalent and about 2m from the table surface
    5. that the candle is lit and projecting light
    6. that the preferred dominant light source is the interior lighting

    Allowing for relative strengths of the light sources I'd hazard a guess (using point lights for the three internal light sources) as being:
    overhead 8%
    lamp 5%
    candle 1%
    exterior scene ambient value anywhere between 1 and 2.

    I know you haven't worked on it yet, but the table lamp light is either in the wrong position or the lamp shade has shadows turned off. Or both. Variable colour temperatures for the three lights will also add a bit to this scene, with warmer colours inside than outside.

    The process I use is outlined here (https://www.sharecg.com/v/84810/browse/3/PDF-Tutorial/Lighting-relationships-in-Poser). It's a bit wrong in places and I'm currently revisiting the whole thing, but it's still pretty close to accurate. I'm also working on calculators that figure out light settings for you, but they're still very much a work in progress. I've done point lights so far (accurate figures now from 1m to 1km), and a calculator that measures distances in 3D space based on the XYZ coordinates in Poser.


  • Poser Ambassadors

    @Glitterati3D said in Dumb question time: Turn an existing object into an area light?:

    Thanks! I know I could do it the easy way (copy) but I really want to learn this and I'm one of those people who has to DO it to understand.

    Ah, yes. I've labeled the nodes to identify them...
    0_1479899738712_demo lamp bulb mat - nodes IDed.PNG

    @matb said in Dumb question time: Turn an existing object into an area light?:

    Yes, I suspected that from looking at some test renders, but they don't seem to have an identical falloff to a point light of the same intensity in the same location.

    You might experiment with scaling up the point light so that its sphere mesh is just slightly larger than (and enveloping) the bulb. Preview the scene from orthogonal cameras in "outline" mode.
    But the mesh light will be more accurate than a pre-P11 point light insofar as distribution of light; no light bulb is actually a single point.



  • @piersyf Thank you, piersyf for the contribution.

    What I really wanted to do was use an "older" (and this set is not old by any means) scene setup and convert it to Superfly to understand HOW to do that.

    In fact, I picked THIS scene because it's very well done, provides some really good interior backdrops for renders, and even has morph controlled running water in the bathroom shower. It's a very well done, well thought out product which was simply released before Superfly and I wanted to learn how to make it work well in Superfly.

    I have simply reached a point where I use Firefly rarely to to render anything and it was time to devote some effort to learning how to convert existing products to look and function well in Superfly. Since this is a product I see myself using for interior backdrops, I felt it was a good learning tool.

    My goal here was to light the scene well for Superfly. Materials and prop positioning were simply left to their default and not a concern at this point, except for the ambient controlled materials on the lights.

    I'm running a render on my latest changes and will post it when finished. Since I'm rendering without GPU it will take a while......

    I thank you for your well thought out comments and look forward to your tutorial!



  • @Glitterati3D
    I understand, and pretty much doing the same thing myself. I've not worked on any of my older projects since Poser 11 came out as many of the scenes didn't work in Superfly but the lighting is far more capable. I've spent most of this year re-texturing existing scenes, and in some cases building them from scratch in Blender.
    Personally I think the secret to lifelike renders is a mesh that is accurate to real world dimensions, good textures and good lighting. I'm pretty average at modelling, but getting better with things like buildings and streets. I'm still learning materials, but find the Superfly materials much easier than the Firefly node noodles. Lighting I could learn and contribute that back to the community. I have studied photography (decades ago) and looked for a way to get Poser lights to behave like real world equivalents (or more accurately, to take any given real world light and accurately represent it in Poser). That's what my tutorial on ShareCG is about. Since publishing that I've discovered that Poser lights all have different illuminance values, and have been plotting them and building them into my calculators.

    I don't have your scene, but I have several bought interiors that I have retextured somewhat for Superfly and set the lighting. I think this is as close as I have to what you are working with:

    0_1479941361672_interior.jpg

    The skydome image has an ambient value of 2 in this render.

    As a hint, I'd suggest placing a cone primitive on your coffee table and setting the material for the cone at 127 in all channels (mid grey) then test render. You want the render to give a return as close to 127 as possible. Get that, and you have the lights at the correct level for the materials used in the room. The rest is just being aware of relative strengths for different light sources.

    BTW, my comment on the table lamp in your scene was because there's no shadow on the wall from the lampshade. Y-phil's bedroom is an example of what I mean.