Loading...
> >

HDRI

mhscspomhscspo Posts: 101
edited May 2013 in Carrara Discussion

In reference to this topic on how to make hdri files (http://www.daz3d.com/forums/discussion/19206/) I would like to know if any of the scene lights are turned off to use the hdri map.

Post edited by mhscspo on

Comments

  • 3DAGE3DAGE Posts: 3,311
    edited December 1969

    HI mhscspo :)

    It depends on whether you want to have directional shadows in your image.

    Ideally, with a good HDRI, all the scene light should be coming from the image alone, but..

    Normally an HDRI, used as scene lighting will emit light from all pixels in the image,. and since it's a 360 degree environment image, the light is coming from all directions,. which gives you an all round light, but no distinct directional shadows.

    You can have multiple scene lights, or just one "directional" light , like the Sunlight,.. and still use HDRI,. or jpg / png etc.. (or a background "colour"),.. it depends on what you're trying to do.,

    Bear in mind that if you have lights, and an HDRI, then you'll need to adjust the strength of the Lights down,. to balance the effect,.

    Also,. whenever you're using HDRI's,. enable the "Sky light", (or carrara won't use the HDRI for lighting)

    Hope it helps :)

  • evilproducerevilproducer Posts: 9,050
    edited December 1969

    And just reiterate what 3dage said, you can use any image type in the scene's background, or even colors or color gradients, and have it behave as an IBL (Image Based Light) or HDRI. The difference is that an HDRI would probably be a bit better due to the higher dynamic range light of the image.


    When you use the Realistic Sky and enable the Skylight function in the Render Room, it's also acting as an IBL.

  • mhscspomhscspo Posts: 101
    edited December 1969

    Thanks to the both of you, that's what I needed to know.

  • ManStanManStan Posts: 0
    edited May 2013

    3DAGE, you know I will argue you ;)

    I use HDRI a lot, and have shown many times good HDRI has directional light.

    And as soon as I input the latest C8.5 beta code, I'll show you lol

    Post edited by ManStan on
  • evilproducerevilproducer Posts: 9,050
    edited December 1969

    ManStan said:
    3DAGE, you know I will argue you ;)

    I use HDRI a lot, and have shown many times good HDRI has directional light.

    And as soon as I input the latest C8.5 beta code, I'll show you lol


    Hey ManStan, Andy did say that ideally a good HDRI does provide directional light. He just listed a couple caveats. Unless maybe you're arguing the opposite, and you think HDRIs can't provide directional light. ;-)

  • 3DAGE3DAGE Posts: 3,311
    edited May 2013

    HI Stan, :)

    no need for 85,. you can use HDRI in 6 / 7 / 8

    Perhaps I should have said "Crisp" directional shadows,.

    HDRI light comes from the entire image, every pixel,. even the ground, so "Normally" the light is diffused, and produces a soft shadow. (no hard, defined edges, and no distinct direction.
    But, if the image is Black with a single bright white area, then it's possible to have a light direction from that white area,. but it won't give you Hard, Crisp, Distinct, directional shadows,..

    Pics to explain what I mean by directional shadows, and example of an "average" hdri lighting effect from the environment

    Pic1 HDRI light

    Pic 2 HDRI plus a distant light

    you'll hopefully see that the HDRI produces a soft shadow from all round, but no directional shadows, or shadows with a defined edge or direction.

    The Distant light, creates Crisp, hard edged , defined, directional shadows.

    HDtest2.jpg
    640 x 480 - 12K
    HDtest1.jpg
    640 x 480 - 11K
    Post edited by 3DAGE on
  • ManStanManStan Posts: 0
    edited December 1969

    Ok, you got me there. I can't get crisp shadows with HDRI.
    But then your 3rd shot shows the issues with using secondary lighting. It takes some doing getting the HDRI shadow to blend with the light shadow.

  • 3DAGE3DAGE Posts: 3,311
    edited December 1969

    I agree Stan ;) LOL

    You need to adjust both to get a good mix of HDRi scene lighting, and the directional (Distant / Sun)

    I think the best way is to use "Soft shadows" on the directional light too, so it blends better with the HDR shadows, but still produces a directional shadow.

    Adding a shader / texture to the surfaces receiving shadows, will also help to make the "two lights" effect,.. less visible.

    HDtest3.jpg
    640 x 480 - 36K
  • 3DAGE3DAGE Posts: 3,311
    edited December 1969

    It's also worth noting that HDR alone won't give you Specular shiny highlight stuff,. but reflection can be used on shaders to create a reflected shiny highlight thing.

    or add a light, like the distant light,.. to create specular shiny highlight stuff, and the directional shadows

    HDtest4.jpg
    640 x 480 - 36K
  • ManStanManStan Posts: 0
    edited December 1969

    And this is why I spend so much time setting up lighting lol

    I don't do photo real, I like to do realistic; if you have to look twice I got it right ;) Part of the problem; and a very minor problem at best, is the default soft shadows settings seem to be wrong for every light. lol

    Just a word of warning, multiple bulbs with soft shadows will eat up some render time ;)

Sign In or Register to comment.