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strange "brighter" line at top of backdrop?

yonashaldyonashald Posts: 39
in Technical Help (nuts n bolts)

Greetings fellow dazers... (Don't know if thats a thing) :P

Anyhow I have an issue, I am currenty making a render that is outside and is therefor using a backdrop, as you can see in the picture (attached file) the render makes some strange "brighter" line at the top, but it only effects the backdrop, do anyone know how to fix this, I have not seen it before, and I tried changing backdrop picture to other sizes, but seems to happen no matter what? 

Hope one of you hardcore dazers can help me out :D

Best regards. :)

backdrop_issue.png
1500 x 36 - 89K

Comments

  • Richard HaseltineRichard Haseltine Posts: 104,509

    Is the backdrop image exactly the same size as the render?

  • barbultbarbult Posts: 25,165

    I have seen this happen before, too. I didn't find a way to resolve it. I ended up just cropping it off with an image editor. I don't know if the backdrop I used was the same size as the new render or not.

  • yonashaldyonashald Posts: 39

    Richard Haseltine said:

    Is the backdrop image exactly the same size as the render?

     

    No why should it be? I mean I see it while it renders as well 

  • yonashaldyonashald Posts: 39

    barbult said:

    I have seen this happen before, too. I didn't find a way to resolve it. I ended up just cropping it off with an image editor. I don't know if the backdrop I used was the same size as the new render or not.

    I' guess I'll try making the backdrop the same size as my render and see if that helps I'll post my observation after. :)

  • barbultbarbult Posts: 25,165
    edited April 29

    Here is a test I did right now in DS 4.24.0.3. The problem ocurrs even when the backdrop image is the same size as the rendered image using it.

    This is the image I put into the backdrop. Click to see full size 2000 by 1500.

    This is the result of rendering an empty scene with that image as the backdrop. Click to see full size 2000 by 1500.

    Backdrop test 2000 by 1500.jpg
    2000 x 1500 - 2M
    Pasture E Background.jpg
    2000 x 1500 - 2M
    Post edited by barbult on
  • yonashaldyonashald Posts: 39

    barbult said:

    Here is a test I did right now in DS 4.24.0.3. The problem ocurrs even when the backdrop image is the same size as the rendered image using it.

    This is the image I put into the backdrop. Click to see full size 2000 by 1500.

    This is the result of rendering an empty scene with that image as the backdrop. Click to see full size 2000 by 1500.

     

    Yeah same here.

  • barbultbarbult Posts: 25,165

    Same problem in DS 2025 Alpha, too.

  • yonashaldyonashald Posts: 39
    edited April 29

    Barbult it looks like it takes a line from the buttom of the picture like it is just repeating it instead of filling it out with the image :/

    made the bg red so it is easier to see, I still don't know how to fix this tho, I mean it shouldn't do it if we are using images bigger or at least the same size as far as I know..

    test.png
    1062 x 900 - 1M
    Post edited by yonashald on
  • barbultbarbult Posts: 25,165

    I saved my test file in 4.24.0.3 and rendered it in the oll 4.22.0.16 general release. 4.22.0.16 does NOT show the same problem.
    I also noticed the the 4.24.0.3 creates a lot of halos around the trees in the backdrop image when it renders the scene. This also does NOT happen in DS 4.22.0.16.
    Unless I've made some mistake in my testing, it appears that Daz Studio handling of backdrop images regressed in quality a lot, somewhere between 4.22 and 4.23. This loss in quality persistes into DS 2025 Alpha.

    Who else still has 4.22 installed to test my testing?

    Backdrop Test with file saved in 4.24.0.3 rendered in 4.22.0.16.jpg
    2000 x 1500 - 2M
  • Richard HaseltineRichard Haseltine Posts: 104,509

    Haloes and an odd wrapping does suggest an  issue with compression or sampling, though I  don't know why it would affect only backdrops (assumiong it does - what happens if you stick the image on a plane?

  • barbultbarbult Posts: 25,165
    edited April 30

    I created a primitive plane and scaled it to the ratio of the image. I rendered from the FRONT orthographic view. I set my render dimensions to the size of the image. I put the image in the Base Color of by plane. I didn't get the plane perfectly scaled to fit my FRONT view, so my render had a tiny set of empty pixels around the outside of the visible image area in the render. Still my render had the anomaly at the top and the halos around the trees. I rendered once to JPG and once to PNG. Both had the same problems, so I don't think is a compression issue. (I rendered in DS 4.24.0.3.)

    Plane with image FRONT view rendered in DS 4.24.0.3.png
    2000 x 1500 - 5M
    Plane with image FRONT view rendered in DS 4.24.0.3.jpg
    2000 x 1500 - 2M
    Post edited by barbult on
  • barbultbarbult Posts: 25,165

    I tried a different image, 2000 by 2000 in my Environment backdrop. I rendered to 2000 by 2000 in DS 4.24.0.3. When I compare the original image with the backdrop render, I see that the problem is not just at the top. Incorrect pixel values are around all four image edges. In this case, there are three rows or columns of incorrect pixels on each image edge edge. I rendered 3 times and saved as JPG, PNG, BMP. All had the problems in DS 4.24.0.3.

  • barbultbarbult Posts: 25,165

    I rendered that same 2000 by 2000 image to 80 by 80 pixels. I saved it as BMP. The rendered image has an obvious pixel value error along each side, this time 1 pixel wide on the small render.
    I guess the forum doesn't allow uploading BMP images. I get "No file selected". I rendered again and saved as PNG. It is easy enough to reproduce this problem, so you should be able to replicate it.

    Backdrop test square 80.png
    80 x 80 - 11K
  • barbultbarbult Posts: 25,165
    edited April 30

    yonashald said:

    Barbult it looks like it takes a line from the buttom of the picture like it is just repeating it instead of filling it out with the image :/

    made the bg red so it is easier to see, I still don't know how to fix this tho, I mean it shouldn't do it if we are using images bigger or at least the same size as far as I know..

    I don't see any way for us ( users) to fix this. I agree that it shouldn't happen, and it didn't happen in a previous version of Daz Studio (4.22). To me, at this point,  it looks like either a Daz Studio code error, an error in one of the libraries they use, or an NVIDIA Iray error.

    Post edited by barbult on
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