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What causes this herringbone / woodgrain effect

Discussion in 'Using Alibre Design' started by dsage, Feb 3, 2020.

  1. simonb65

    simonb65 Alibre Super User

    Anti-Aliasing has an effect on it, maybe the graphics card settings are different, but if you just enable it in AD, it removes the stripes and just leaves jaggies ...

    AA in Design = OFF


    AA in Design = ON

    Strangely, if you turn AA in Design back OFF, you don't get the stripes until you close and reload the model!!!!


    ... or just go in and enable Ground Shadow ...

    So, something weird in how HOOPS is setting up the graphics pipeline or even scaling the textures for the ambient occlusion effect. Saying that, it looks like the draw order of the model is back to front too!!
  2. JST

    JST Alibre Super User

    Draw order, OR just permanently enabling "all" edges, instead of "visible edges only", if I am interpreting your comment rightly.
  3. JST

    JST Alibre Super User

    I do not see that it is much different. Before re-opening, only the tube portion had stripes. After save reopen of assy, everything dos. Jaggies appear with the base selected.

    Attached Files:

  4. simonb65

    simonb65 Alibre Super User

    I've tried altering all the NVIDIA 3D settings, but nothing improves it. Whatever it is, if you toggle to Perspective View, the density of the stripes just goes insane! So, I'm still sticking to a scaling theory (why it does it on some machines and not others, I don't know ... DPI settings??). But those visible hidden lines though!

  5. simonb65

    simonb65 Alibre Super User

    Draw order. I have my view set to Edge and Face display ...

  6. JST

    JST Alibre Super User


    This is the same sort of thing that I mentioned in the "transparency issues" thread. Added to these things was a flat-out transparency applied to certain parts, possibly in certain orientations.

    Max said the [problem was "very wonky", and there has been no update on the matter since.
  7. idslk

    idslk Alibre Super User

    hoops with everything to max:
    one little part shifted to the left side...

    and the part a little bit more to the right side...


    plus ambient occlusion


    part back to left side and ambient occlusion on gives the same as the first picture...
    simonb65 likes this.
  8. simonb65

    simonb65 Alibre Super User

    Interestingly, I've saved the assembly and sub parts to another folder. Created a new assembly and brought in all the parts (no changes to their settings). Just placing them so that ambient occlusion can be seen at the intersections of those parts, and all is OK ...


    Which suggests the issue may lie in the assembly somewhere, as opening the original assembly (saved as version) still shows the issue.
  9. Max

    Max Administrator Staff Member

    I have a theory that somehow some internal setting is making the display pipeline think the model is much, much smaller (like 3 orders of magnitude) than it is and as a result these weird display artifacts are showing up. Increasing the bounding box of the assembly seems to remedy the issue. It is indeed very strange and likely a HOOPS bug. We're following up with them.

    There's a few ways to get somewhat similar behavior arbitrarily, for example offset 2 faces by .00001" and then zoom way out - the precision required at subpixel depths to figure out which face is in front of which face becomes a challenge - but doing that is somewhat arbitrary and not often an issue - figuring out how this got into this state will be the challenge. We've seen a total of 2 cases of this since shipping the last version, so it's not rampant. It also doesn't appear to be consistently reproducible by folks here, though I can reproduce it.
    simonb65 likes this.
  10. simonb65

    simonb65 Alibre Super User

    That's 90% of the battle won!
  11. jc-s

    jc-s Member

    I also get this with an nVidia Quadro P2000. Just openend the test file using the default settings.

    I have seen strange artefacts from time-to-time, but nothing this bad before.

  12. anson

    anson Member

    I don't think it's graphics related because my poor ATI Radeon HD 4300/4500 Series displays it nicely. One thing I did notice, some of the faces were missing until I clicked on the isometric view, then all cleared up.
  13. tk1247

    tk1247 Member

    I can confirm the same results as jc-s on my nVidia Quadro P2000, latest drivers, latest AD Expert version, HOOPS, all settings at max, just read the file in without tweaks. If I turn off ambient occlusion, I get the transparency issues, as reported here.
  14. Jasper

    Jasper Member

    So...given all this, are there any guidelines or recommendations then on which GPU's to buy? My video card just gave up the ghost, and I don't know what I should get as a replacement.

  15. DavidJ

    DavidJ Alibre Super User Staff Member

  16. Jasper

    Jasper Member

    Yes I read that but it's not very specific and it sounded like the discussion here pointed to specific cards that did or did not work.
  17. DavidJ

    DavidJ Alibre Super User Staff Member

    I run an Nvidia GTX1050Ti - currently it does suffer the effect that is the subject of this thread, but generally is OK for me (my main consideration when buying was noise minimisation so I was limited to fanless cards). As noted in the system requirements, a card with more memory would be preferred if using a 4K monitor, so something a bit further up the 1000 series from Nvidia. No reason why an equivalent AMD card shouldn't work if you prefer.

    I'm sure others here will chip in with cards they are using that cope well.
  18. JST

    JST Alibre Super User

    The GTX 1660 Ti with 6gB has the effect, too.

    Are we saying that the problem is in the video cards? I specifically got this one because it would work with the new graphics system. Is that now out the window?
  19. DavidJ

    DavidJ Alibre Super User Staff Member

    JST - I'm not saying it is the card, though some have suggested that. Jasper was asking for some specific suggestions regarding graphics card to purchase. I juts told him what I have - and since in this thread it seemed only fair to mention it does show this effect.

    The visual effect that this thread is mainly about seems to be more complex (see Max's post earlier) - hopefully Development can work out what is happening in this case and make improvements.
  20. bigseb

    bigseb Alibre Super User

    Don't worry about your graphics card, its plenty powerful.

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