Page 1 of 2 12 LastLast
Results 1 to 15 of 28

Thread: Daytime moon

  1. #1
    Curmudgeon in Training Ma3rk's Avatar
    Join Date
    Mar 2003
    Location
    Near Beaverton, OR
    Posts
    1,442

    Daytime moon

    I'm looking for some pointers on how to set up a node surface for a billboard of a 3/4 waining full moon in daytime. If you're where it's clear & noticed (been happening the past few days), the shadow portion just blends into the blue sky.

    In After Effects, I'd do something with a luma & alpha mattes, but not sure quite how to go about that in LW. I kinda sorta have it working but not with the contorl I'd like.

    TNX
    "Never be a cat in a cartoon. Never." Chief Wiggum

  2. #2
    RETROGRADER prometheus's Avatar
    Join Date
    Aug 2003
    Location
    sweden stockholm
    Posts
    15,128
    Quote Originally Posted by Ma3rk View Post
    I'm looking for some pointers on how to set up a node surface for a billboard of a 3/4 waining full moon in daytime. If you're where it's clear & noticed (been happening the past few days), the shadow portion just blends into the blue sky.

    In After Effects, I'd do something with a luma & alpha mattes, but not sure quite how to go about that in LW. I kinda sorta have it working but not with the contorl I'd like.

    TNX
    Fake it with transparency..if nothing is
    Behind the moon.
    Or if using hv sprite clip..try dissolve.

    Ive done this ages ago.
    At work having lunch..so I can't give
    A Proper showcase right now.

  3. #3
    RETROGRADER prometheus's Avatar
    Join Date
    Aug 2003
    Location
    sweden stockholm
    Posts
    15,128
    You should also use light incidence angle for any such gradient in dissolve or trasnsparency channel.

  4. #4
    'the write stuff' SBowie's Avatar
    Join Date
    Feb 2003
    Location
    The stars at night are big and bright
    Posts
    19,404
    Quote Originally Posted by Ma3rk View Post
    If you're where it's clear & noticed (been happening the past few days), the shadow portion just blends into the blue sky.
    You know I'd never thought about this, yet it sounds right - which (at risk of a tangent) makes me wonder why this is so ... I could guess, but does anyone know the physics (or optics) involved?
    --
    Regards, Steve
    Forum Moderator
    ("You've got to ask yourself one question ... 'Do I feel lucky?' Well, do ya, spammer?")

  5. #5
    I don't know exactly why but if the shadow portion of the moon is as black as the rest of the sky around it then atmosphere "filter" is applied equally to both the black sky and black part of the moon making them both the same. I think?
    On some days when the shaded part of the moon is not as black and you can actually see it, also colored blue.
    Wasn't there a tutorial on exactly this in an very very old LW book (no nodes, though)?

  6. #6
    RETROGRADER prometheus's Avatar
    Join Date
    Aug 2003
    Location
    sweden stockholm
    Posts
    15,128
    Quote Originally Posted by SBowie View Post
    You know I'd never thought about this, yet it sounds right - which (at risk of a tangent) makes me wonder why this is so ... I could guess, but does anyone know the physics (or optics) involved?
    Probably the same reason we do not see the dark space...atmospherics.
    And it will tint cover anything thst doesnt emitt light strongly enough.

    In the 3d world...a sk.sunsky is purely a backdrop
    ..we would need volumetrics to make the moon fade away where it is in a veil of shadows...and actually a strong light or volumetric light to simulate rays from the moon...and in such case it wouldnt work with a luminous surface on a sphere.

  7. #7
    RETROGRADER prometheus's Avatar
    Join Date
    Aug 2003
    Location
    sweden stockholm
    Posts
    15,128
    The basic stuff....though if you want something advanced such as a two moon or more moons hanging in a scifi-scene, and one moon obscuring the other, this wonīt be working so good with transparency.

    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	moon.jpg 
Views:	153 
Size:	184.4 KB 
ID:	143255  

  8. #8
    Curmudgeon in Training Ma3rk's Avatar
    Join Date
    Mar 2003
    Location
    Near Beaverton, OR
    Posts
    1,442
    Quote Originally Posted by SBowie View Post
    You know I'd never thought about this, yet it sounds right - which (at risk of a tangent) makes me wonder why this is so ... I could guess, but does anyone know the physics (or optics) involved?
    I'm pretty sure it's just the refraction & skattering of the sky color; similar to why when looking into a hole poked in snow on a clear day looks blue too. I know we covered this in my college physics, but that was way too many decades ago.
    "Never be a cat in a cartoon. Never." Chief Wiggum

  9. #9
    Axes grinder- Dongle #99
    Join Date
    Jul 2003
    Location
    Seattle
    Posts
    14,734
    When the Moon is visible during (Earth) day, there's probably a fair amount of "Earthshine" hitting the moon, because obviously the Earth is quite bright at such times.

    TO THE INTERNET!!!

    "The Earth is much brighter in the Moon's sky than the Moon in Earth's sky. Not only is Earth 3.6 times 13 times larger by angular area, but its average albedo of 0.37 (meaning Earth reflects 37% of the Sun's light on average) is more than three times higher than the Moon's (0.11)."
    They only call it 'class warfare' when we fight back.
    Praise to Buddha! #resist
    Chard's Credo-"Documentation is PART of the Interface"
    Film the cops. Always FILM THE COPS. Use this app.

  10. #10
    Curmudgeon in Training Ma3rk's Avatar
    Join Date
    Mar 2003
    Location
    Near Beaverton, OR
    Posts
    1,442
    Quote Originally Posted by prometheus View Post
    You should also use light incidence angle for any such gradient in dissolve or trasnsparency channel.
    I'll look into that. At the moment I've been just using a gradient.

    The scene is using an HDR enviro light & a Texture Environment for the bg and just using GI so not sure how you'd set incident angle for that.

    The billboard of the moon is a pretty high rez HDR as well an at present just using a Standard material. I am using some object dissolve (~38%) for transparency to blend but running into the issue of if I get the dark side to look correct, it's not bright enough for the lit side. I can kick that up some on the image map but it still wasn't right.

    I've a very subtle volumetric fog for atmospheric and letting that affect the moon object, so distance from camera becomes a factor.

    Ignore ground at present. That's a WIP. Still discovering some UV & texturing issues too.

    Click image for larger version. 

Name:	MainSt_LastestMoon.jpg 
Views:	48 
Size:	438.7 KB 
ID:	143258
    "Never be a cat in a cartoon. Never." Chief Wiggum

  11. #11
    RETROGRADER prometheus's Avatar
    Join Date
    Aug 2003
    Location
    sweden stockholm
    Posts
    15,128
    Quote Originally Posted by jeric_synergy View Post
    When the Moon is visible during (Earth) day, there's probably a fair amount of "Earthshine" hitting the moon, because obviously the Earth is quite bright at such times.

    TO THE INTERNET!!!

    "The Earth is much brighter in the Moon's sky than the Moon in Earth's sky. Not only is Earth 3.6 times 13 times larger by angular area, but its average albedo of 0.37 (meaning Earth reflects 37% of the Sun's light on average) is more than three times higher than the Moon's (0.11)."
    To me it doesnīt sound reasonable that such earth shine would yield any significant energy for the moon to emitt that earth shine light back strongly enough to be visible in earth atmosphere.
    It would be secondary reflected light, sunlight first hits the earth and then need to travel to the moon, then reflect that "earth shine"light again back through earth atmosphere, and for the earth to have a full cycle of the whole earth shine, I suspecty the sun would need to be behind the moon in a straight line I guess, and thus it will loose any direct sunlight, leaving it with only the earth shine light to illuminate the moon, and maybe a slight rim light on the side of the moon.

    So I just donīt think that earth shine is contributing in a significant way to the appearance of the moon blending in to the earth atmosphere, picking up the same color which sort of gives the illusion of fading away.

    I am guessing itīs just air refraction together with atmosphere thickness that determines which light and how much is penetrating enough to be visible.

    I am no expert in physics though, so from me it is foremost guessing.

  12. #12
    Electron wrangler jwiede's Avatar
    Join Date
    Aug 2007
    Location
    San Jose, CA
    Posts
    6,515
    Quote Originally Posted by prometheus View Post
    Probably the same reason we do not see the dark space...atmospherics.
    And it will tint cover anything thst doesnt emitt light strongly enough.
    Exactly. The scattered sunlight in the atmosphere effectively "drowns out" both the darkness of space, and the darkness of the moon's shadow in the same manner. The only way things show through the atmosphere is if they're adequately brighter than the atmosphere's brightness level (also why celestial objects aren't typically visible during daytime).

    Darkness is the absence of light.
    Last edited by jwiede; 11-01-2018 at 01:22 PM.
    John W.
    LW2015.3UB/2019.1.4 on MacPro(12C/24T/10.13.6),32GB RAM, NV 980ti

  13. #13
    RETROGRADER prometheus's Avatar
    Join Date
    Aug 2003
    Location
    sweden stockholm
    Posts
    15,128
    Quote Originally Posted by jwiede View Post
    Exactly. The scattered sunlight in the atmosphere effectively "drowns out" both the darkness of space, and the darkness of the moon's shadow in the same manner. The only way things show through the atmosphere is if they're adequately brighter than the atmosphere's brightness level (also why celestial objects aren't typically visible during daytime).

    Darkness is the absence of light.

    Yup...

    Maybe this may be helpful..though the question "Why transparent" actually is a false conclusion, and for the false world, transparent is exactly what the moon object is in my sample here, as a fake for the lack of atmospherics.
    https://www.quora.com/Why-can-you-se...it-transparent

  14. #14

    Cool Blood Red Day Moon...edge blending...LightWave...SpeedEDIT...father sun also...

    Who can forget the daytime blood red moon over the pyramids quite the blend-in also...:








    Last edited by Shawn Farrell; 11-01-2018 at 04:44 PM.

    NDI Camera
    TriCaster Mini Advanced Edition
    Lightwave 11
    SpeedEdit 2.5

    Music by www.soundtraxxmusic.com

  15. #15
    Curmudgeon in Training Ma3rk's Avatar
    Join Date
    Mar 2003
    Location
    Near Beaverton, OR
    Posts
    1,442
    I switched to a Delta material for the moon object, and that with some matte & luma manipulation into a gradient for surface transparency is getting there. Think I need to kick the volu fog up just a bit or tweek distance settings. In any case, I'm just bummbling along with this so open to better techiques.

    Knocked the main enviro light down some as well.

    Click image for larger version. 

Name:	MainStreetCorner.jpg 
Views:	42 
Size:	346.5 KB 
ID:	143265
    "Never be a cat in a cartoon. Never." Chief Wiggum

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •