Announcement

Collapse
No announcement yet.

mistakes

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • mistakes

    hello forum i have two issue i cant seem to resolve.

    1.this what i normally do: setup scene, add lights, add materials, fix camera exposure, render. before i do anything i add a vray sun and link it to the background and GI tabs. somehow i cant get light to reach far inside my scene from the gi. if i change the camera exposure to make the scene brighter everything looks washed out. how would you make the scene brighter without adding lights or changing the exposure? ( i tried the rectangular lights trick but it just adds a lot of noise)

    2.I have this image which has several mistakes but i don't know how to fix them.
    A.The first problem is the hard shadows on the walls. those shadows come from spot lights on the ceiling. i have tried everything i know to soften those shadows but nothing works.
    B.another thing is the overly dark regions on the image like on top of the refrigerator and stove. i have 6 spotlights and 2 spherical lights inside + vray sun coming in from one window and i still get these dark areas. I think these areas shouldn't be so dark since i have a lot of lights sources and light/reflective materials which allow light to bounce around the scene.

    Here is a link to the image since i cant attach files to threads
    https://www.dropbox.com/s/ou69x3wpu6...%20shadows.png

    I just want to know what is a good approach to fix these things or anything you think might work. this was rendered with vray 1.5 for rhino.

  • #2
    1. by definition you can't make the scene brighter without either changing the lights or the exposure. Not sure why adding the rectangular lights at the windows would add noise, but an alternate fix is to use the Exponential or HSV Exponential color mapping settings to allow the interior to be exposed correctly without washing out the exterior.

    2.A. the fact that the shadow reaches all the way to the window and the uniform brightness of the scene (spotlights should make the lower areas of the render much brighter than the upper parts of the render) suggest that decay is not set correctly. make sure the decay is set to inverse or inverse square (and increase brightness accordingly to compensate). no decay (linear) can cause this uniform brightness.

    also, some notes about shadows: the shadow radius is set in model units, check your units and make sure your radius isn't unreasonably large (significantly larger than a normal sized light bulb). also note that shadow softness is not just affected by shadow radius, but by the proximity of the shadow-casting object to the shadow-receiving surface. if the distance is close, as in your scene, it's very possible for a light with significant radius to still cast a hard shadow. that's what seems to be happening in your scene. I'd suggest using a rectangular light instead of spot lights (spot lights cast hard shadows, after all).

    you might have to turn the lights on one by one in order to diagnose which lights are offending.

    2.B. the "overly" dark area above the kitchen hood looks correct to me. the spot over the fridge looks weird, i'd guess it's your IRmap or LC settings, can you post them? were you saving/re-using the calc?
    emil mertzel
    vray4rhinoWiki

    Lookinglass Architecture and Design

    Comment


    • #3
      Hey I remember you. Thanks for your help. I guess public users don't get much love from chaos group ok.

      I think i get those dark areas because my windows are kind of small. I'm going to add more windows and see what happens.
      I prefer Reinhard over exponential or HSV because I have gotten good results before and it is easier to control burned out areas with it.
      All the interior lights are set to inverse square. Anything else produces unrealistic lighting.

      I was able to figure out how to get soft shadows from spot lights using the radius settings. I made this before I saw your post.
      https://www.dropbox.com/s/dnicbhzsfa6lmvh/b.0000.png ( no ps)

      I think for irradiance map I'm using 120 and 30. And the light cache I think is 1500 and .001 then everything else is default. I think letting in more natural light might soften this dark area. I would do more test but this image takes 2+ hrs to complete.

      Comment


      • #4
        It's not just the public forum, they only check the forums once in a while. Glad it was just the radius, though I'm puzzled by the original image

        your settings seem super high, especially light cache.

        GL!
        emil mertzel
        vray4rhinoWiki

        Lookinglass Architecture and Design

        Comment

        Working...
        X