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  • Red Shadows

    I'm having an issue with a material in that I'm getting red shadow areas. I've rendered the scene with two other darker materials with no issues, so I can't imaging it's anything with lighting. In fact, if you look at the gap between the two file drawers, you'll see it there. The material itself is nothing fancy - just a bitmat in the diffuse slot. I'm using the default BF/LC setup with 3.40.02

    Any ideas as to what's going on?

    Click image for larger version

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    Last edited by Streetwise; 30-06-2016, 05:19 AM.
    David Anderson
    www.DavidAnderson.tv

    Software:
    Windows 10 Pro
    3ds Max 2024.2.1 Update
    V-Ray GPU 6 Update 2.1


    Hardware:
    Puget Systems
    TRX40 EATX
    AMD Ryzen Threadripper 3970X 32-Core 3.69GHz
    2X NVIDIA GeForce RTX 3090
    128GB RAM

  • #2
    That looks like there's a non-vray material in the scene?
    Check out my (rarely updated) blog @ http://macviz.blogspot.co.uk/

    www.robertslimbrick.com

    Cache nothing. Brute force everything.

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    • #3
      Is there an easy way to find that? Or is it better/easier just to fire up V-Ray scene converter?

      Edit: I just ran scene converter, but no difference to output.
      Last edited by Streetwise; 30-06-2016, 06:28 AM.
      David Anderson
      www.DavidAnderson.tv

      Software:
      Windows 10 Pro
      3ds Max 2024.2.1 Update
      V-Ray GPU 6 Update 2.1


      Hardware:
      Puget Systems
      TRX40 EATX
      AMD Ryzen Threadripper 3970X 32-Core 3.69GHz
      2X NVIDIA GeForce RTX 3090
      128GB RAM

      Comment


      • #4
        Isn't that just how Lightcache works? It usually produces quite saturated shadows. As a test you could use BF instead of LC for the secondary GI, see if that fixes it.

        Comment


        • #5
          Originally posted by Laserschwert View Post
          Isn't that just how Lightcache works? It usually produces quite saturated shadows. As a test you could use BF instead of LC for the secondary GI, see if that fixes it.
          BF/BF didn't do anything either except slow the render WAY down... What DID seem to help however, was to turn GI Saturation from 1.0 to .5 This made a big difference, but I'm not sure if that's the "right way" to fix it? Even though the color is less noticeable, the shadows are still "reversed" in that they are actually lighter in some spots.
          Last edited by Streetwise; 30-06-2016, 08:46 AM.
          David Anderson
          www.DavidAnderson.tv

          Software:
          Windows 10 Pro
          3ds Max 2024.2.1 Update
          V-Ray GPU 6 Update 2.1


          Hardware:
          Puget Systems
          TRX40 EATX
          AMD Ryzen Threadripper 3970X 32-Core 3.69GHz
          2X NVIDIA GeForce RTX 3090
          128GB RAM

          Comment


          • #6
            I wonder if you try using override material and put a white material as GI override and see if that handles it. It may just work, at which point you have at least worked out what the problem is and maybe a solution can be arranged from there.

            Comment


            • #7
              looks like your lighter material is just way to bright. resulting in producing too much gi. what are the rgb values on this bitmap?
              Last edited by piotrus3333; 01-07-2016, 12:23 AM. Reason: typos
              Marcin Piotrowski
              youtube

              Comment


              • #8
                Originally posted by piotrus3333 View Post
                looks like your lighter material is just way to bright. resulting in producing too much gi. what are the rgb values on this bitmap?
                They are 235, 193, 144. I'll have to try colorcorrect and maybe darken a bit, and then bring the levels back up in post. I'd rather keep it fairly simple whatever the fix may be.
                David Anderson
                www.DavidAnderson.tv

                Software:
                Windows 10 Pro
                3ds Max 2024.2.1 Update
                V-Ray GPU 6 Update 2.1


                Hardware:
                Puget Systems
                TRX40 EATX
                AMD Ryzen Threadripper 3970X 32-Core 3.69GHz
                2X NVIDIA GeForce RTX 3090
                128GB RAM

                Comment


                • #9
                  too high imho. I consider 160 good value for simple white interior wall. and that wood is darker than white wall. and it is fairly simple: correct input gives you correct result.
                  what does your color mapping look like?
                  Marcin Piotrowski
                  youtube

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                  • #10
                    by 160 I mean color directly in color swatch of VRayMat diffuse. it will be higher if that would be texture used in diffuse slot - gamma corection.
                    If you don't like to be bothered by math prepare 3 simple gray VRay materials in editor slot: rgb 56 (half gray), 160 (white interior wall) and 185 (common white paper) and use those as reference for brightness of your shaders. Than use rgb multiplier and/or curve in output section of max's bitmap leader.
                    Marcin Piotrowski
                    youtube

                    Comment


                    • #11
                      Any chance the xform is way off? Maybe reset it?

                      Comment


                      • #12
                        Originally posted by piotrus3333 View Post
                        too high imho. I consider 160 good value for simple white interior wall. and that wood is darker than white wall. and it is fairly simple: correct input gives you correct result.
                        what does your color mapping look like?
                        I think you've hit on the issue. I put a Color Correction on the material and turned the brightness and saturation down by 25%, Contrast down 10%. WAY better. I don't seem to have any of those issues. Since I'm outputting to 16-bit, I was easily able to then "pull" the material levels back up to the RGB values of the swatch without issue. Thanks.
                        David Anderson
                        www.DavidAnderson.tv

                        Software:
                        Windows 10 Pro
                        3ds Max 2024.2.1 Update
                        V-Ray GPU 6 Update 2.1


                        Hardware:
                        Puget Systems
                        TRX40 EATX
                        AMD Ryzen Threadripper 3970X 32-Core 3.69GHz
                        2X NVIDIA GeForce RTX 3090
                        128GB RAM

                        Comment


                        • #13
                          now with darker diffuse colours you can boost the lights to get previous exposure.
                          I'm glad I could help.
                          Marcin Piotrowski
                          youtube

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