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Iray Cutout Opacity property sometimes fails? (SOLVED - for me anyway...)

john_antkowiakjohn_antkowiak Posts: 336
edited December 2017 in Technical Help (nuts n bolts)

Hi. I've noticed this on occasion but in my current project it's a big problem. I'm not sure if this is always the case, but this time I'm using a set designed for 3Delight, with all surfaces converted for Iray using the DAZ Uber Shader Preset. I render in Iray. The set is House of Barlow by The Management. There are a variety of wall textures in this set, but only one without doors or windows. But this wall also has a material zone for "details" which covers the wall in picture frames and light fixtures. Normally I just set the Coutout Opacity of this material zone to 0. The unwanted details disappear and it's good to go. 

But sometimes I get this strange ghost effect and I can't figure out how to get rid of it. The first image shows a spot render revealing the "shadow" of the hidden details; the second is the viewport view with the problem surface highlighted. I tried removing all maps from the channels (bump, normal, etc.) but that had no effect. Any ideas?

coutout opacity shadow 01.jpg
1366 x 768 - 299K
coutout opacity shadow 02.jpg
1366 x 768 - 232K
Post edited by john_antkowiak on

Comments

  • macleanmaclean Posts: 2,438

    At one point I had a similar problem, and I added a full black .jpg to the Cutout channel, which cured the issue. However, that was in an older version of DS, and I haven't seen it since. I don't know whether something has changed in the program or I've been lucky, but a black jpg might be worth trying.

  • Richard HaseltineRichard Haseltine Posts: 111,282

    It might better to use the Geometry Editor to hide those polygons, then remove the hidden polygons, export as OBJ, reimport, reapply materials, and save as a new asset - that way you can make a ready-to-load plain wall.

  • john_antkowiakjohn_antkowiak Posts: 336

    First, with apologies to MacLean, for some reason when I checked the replies I only saw Richard's and thus didn't even try the black .jpg technique. I'll keep it in mind to try next time it happens. Very oddly, I found that the issue seems to come and go with different lighting. When I hid the roof and exposed the wall to the HDRI lighting, the shdows disappeared. I tried a bunch of other lighting combinations, and it varied. The roof is a sort of dome-shaped affair - maybe not spherical; I don't know - split in halves. So I made one half emissive to light the interior, along with some other emissives... and no shadows. I tried placing an emissive table lamp directly under it (you can see th table in the original image), but the shadows remained. So I don't know. But it's a non-issue at this point. Thank you for your thoughts, gentlemen --

    Incidentally, the scene is meant to be used as a family portrait in another scene set in the same place...

    Wayne Family Portrait.jpg
    1334 x 2160 - 3M
  • 3WC3WC Posts: 1,164

    Anybody ever figure this out? Sorry to bring back the thread, but I am getting a similar problem. I have a plane that is casting shadows even at zero opacity in iray, and I am about to pull my hair out. I also have a cutout opacity map, but to no avail. :(

  • WendyLuvsCatzWendyLuvsCatz Posts: 41,466

    well you could check stuff like highlight, specular, reflection etc, I'd apply DZ default to that surface myself and have as few parameters as possible 

  • john_antkowiakjohn_antkowiak Posts: 336

    Hi, 3WC. Did you ever get this worked out? Richard's suggestion is the one I normally use now. It should work for you too, assuming that the plane you refer to is one you don't want visible in your scene. In my OP I had some that were present but hiden because they were undesired. The simplest way to take care of that was to use the Geometry Editor, but I find I don't have to use all the steps Richard suggested. There are various ways to select the surface you want to hide. Once I have them selected and hidden, I delete them from the scene and save the scene. (That's Save, not Export.) Polygons hat aren't there, don't cast shadows.

    Does that help?

  • 3WC3WC Posts: 1,164

    Lol, you know, I don't even remember what I was working on, so I must have figured it out.

    I forget that there is no automatic subscription even to the threads you reply to, I was surprised to open this and see I had commented here.

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