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IRAY: Extremely long rendering times with primitives

RCR-2631227RCR-2631227 Posts: 212
in Daz Studio Discussion

Hi all, i'm sure i wong something because is absolutely absurd.. With an GTX 1070 and an i7 4790k, the rendering times with default Iray settings with only an HDR preset, for G3 without floor and wall, are really fast, about a minute and a half but, when i create the cube primitives for the walls and floor, the rendering times become incredibly long, also over ten minutes! This is very strange because if i import an object, maybe a furniture or a little cube, the rendering times are ever fast! That happen only when i close the character into 2 cubes for the walls and 1 for the floor!

Where i wrong? Is normal that?

Comments

  • ToborTobor Posts: 2,300

    Iray renders fastest when the subject is lit with direct light. When you put objects around the subject, these objects block some of the light. There is still light in the scene, but now it's indirect, and this takes additional ray tracing calculations to perform.

  • RCR-2631227RCR-2631227 Posts: 212
    Tobor said:

    Iray renders fastest when the subject is lit with direct light. When you put objects around the subject, these objects block some of the light. There is still light in the scene, but now it's indirect, and this takes additional ray tracing calculations to perform.

    And i have some chances for "fix" that? It's very problematic that thing..

  • Richard HaseltineRichard Haseltine Posts: 102,464

    Put some lights in the room, if that is acceptable for your vision.

  • Oso3DOso3D Posts: 15,042

    I'm still trying to process incredible long render times of 10 minutes.

    Um.

    Along with what Richard said, another approach is to use ghost lights (emitting primitives with Cutout Opacity set very low -- it sheds light, but you don't see the light source). That can help 'fill' an area with light without an obvious source.

  • oomuoomu Posts: 175

    When you add "geometry" (walls and so on, whatever it's a primitive or a huge complicated 3D mesh), you add indirect lighting : lights bouncing from the source on the surfaces to your character and so on.

    It's what iray is made for : realistic lighting (it means indirect lighting : light from bouncing on objects) and yes, the most your scene is complicated, the most it will take time to render without too much noise.

     

    The more you add lights, the more noise disappears quickly in the render. So you could add lights in surfaces (mesh light) or a point light to fill shadows slightly. It depends of the result you want.

    -

    you shouldn't frown upon indirect lighting: it allows you to create moody settings, interesting back light, to create an atmosphere for your scene. Ten minutes is nothing in raytracing rendering. A great scene with careful and tasteful use of lights and props could ask you one or even many hours of rendering. Even with a gpu.

     

  • ben98120000ben98120000 Posts: 469

    You can also change Max Path Length (Render setting tab - Optimization menu) value to something like 16. Default value of -1 means "unlimited", which takes time.

  • TheKDTheKD Posts: 2,696

    I got a 1070, scenes that are indoors always just take me hours, even with ghost lights :(        I give up with it, and just compose my scenes so I can use just a floor and one or 2 walls now, if I can't just do an outside version of it lol.

  • kitakoredazkitakoredaz Posts: 3,526
    edited May 2017

    I felt same  thihg now days.,,,   about just a simple  close indoor room scene, (2 window) with HDRI only, before I do not feel such  stress with 980ti X 2

    but  nowdays,, as if I retun to those days  I could render with  cpu only.    then which driver are you using now? (feel significant slow down)

    I keep up-date dirver, after daz release 4.9,,, but feel if  nvidia driver (for windows 10) cause problem. 

    my driver version is 381.65

     

     

    Post edited by kitakoredaz on
  • kitakoredazkitakoredaz Posts: 3,526

    And,, I can not get same quarity render image as viewport iray render ,, after I start render 5 minutes later.  (I feel all mat are laready loaded) the image in render window seems less quarity,than current 3d viewport (untill I start render,,) photorial,, I feel something wrong. 

    I tried to use iray light portal etc,, but it do not offer any speed for me.  or I can not wait to finish render to comare with non portal render image.

  • ben98120000ben98120000 Posts: 469

    Viewport renders are usually much smaller than final renders, hence the speed difference.

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