3 Replies Latest reply on Apr 18, 2010 11:06 AM by Mylenium

    Proper way to blend in z-depth fog.

    Lehm2000

      I'm putting a 3d object into some footage.  I've got a z-depth pass rendered out that I'm attempting to screen ontop of the rendered 3d object.  The problem I'm having is that this results in a white halo around the object when setting maintain transparency because the background of the z-depth is white.  I'm not really sure what to do about this.  Other than just render the object with the fogging baked in, but I'd rather have the control of doing it in post.

        • 1. Re: Proper way to blend in z-depth fog.
          Mylenium Most Valuable Participant

          I'm putting a 3d object into some footage.  I've got a z-depth pass rendered out that I'm attempting to screen ontop of the rendered 3d object.  The problem I'm having is that this results in a white halo around the object when setting maintain transparency because the background of the z-depth is white.  I'm not really sure what to do about this.  Other than just render the object with the fogging baked in, but I'd rather have the control of doing it in post.

           

          Why use the retain transparency option?  No point in it at all. This switch is merely meant for effects that may overwrite Alpha channels. For what you want, you simply assign the Z-buffer as a luma matte to the object layer and that's it. you can control the depth by using Levels or otehr effects on the matte layer then.

           

          Mylenium

          • 2. Re: Proper way to blend in z-depth fog.
            Lehm2000 Level 1

            hmm. Wouldn't that just result in my rendered object being semi transparent?

            • 3. Re: Proper way to blend in z-depth fog.
              Mylenium Most Valuable Participant

              It's the same how Z-buffer fog works in 3D programs - blend in the background color based on the depth. If, for some reason you don't want to affect the object, then add a solid on top and apply the inverted luma matte to the solid.

               

              Mylenium