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Discussion in 'Lenovo (IBM)' started by kurt corbin, Nov 21, 2019.

  1. Shogmaster

    Shogmaster Pen Pro - Senior Member Senior Member

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    Guys when I concocted that jitter test, I knew that the biggest problem with the test is the human input. So I tried my best to draw at same speed between two machines. But even with that, it's not super reliable due to speeding up and slowing down while drawing to meet my 6 second duration I gave myself. I also tried to keep the pressure level constant but that was undoubtedly variable between tries, and I do think that also somehow effects number of nodes.

    What I'm saying is, it might be problematic comparing input between 2 different people on 2 different digitizers, even if the duration and length is the same.

    I think a much better test would be somehow being able to see the digitizer grid and photograph it against a ruler. I know that some MPP digitizer in bright sunlight can reflect the digitizer grid to naked eyes. I would hope that all the pro cap digitizers since they rest on the surface of the glass can be visible in certain lighting and can be photographed.

    I think we as a community should investigate methods to make the digitizer grid visible easily.
     
  2. ricarva

    ricarva Pen Pal - Newbie

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    @Shogmaster @Qyygle

    Here's a capture from the MS Whiteboard app on my C940 14 with UHD screen.

    The longer lines on the left were done with the help of a ruler, and show some sort of high frequency tremor that I'm working with Lenovo tech support to try and figure out (maybe pen, maybe digitizer; might have to send the whole thing in for repair/replacement). As it stands, I find the device's performance on this issue completely unacceptable.

    I've been looking at the discussions around grid density, and have come up with a couple of doubts.

    Can we be sure that the line waviness has to do with the density per-se?

    Do we know if Clip Studio's vector layer captures all the pints reported by the digitizer, or is actually just computing the nodes needed to represent a given curve? Unless there's some info from the developer stating the former, I'd go with the latter since that's consistent with what we do know: a wavier line in vector format usually needs more nodes than a straighter one!

    Another thing that we know is that different pens on the same digitizer can give results worlds apart: from damn-near perfect lines to super-wavy ones at the change of a stylus. Wouldn't that point to some sort of matching being needed between the screen/digitizer and specific pens?

    Thanks in advance for your insights and inputs.
     

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  3. ATIVQ

    ATIVQ V⅁O⅄ Senior Member

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    Nope. While a denser grid should be easier to make more accurate, it doesn't mean a less dense grid is always less accurate. Wacom EMR has a VERY sparse grid (in some cases one gridline every centimeter!) and it interpolates slow diagonal lines properly. Some systems have extremely wavy lines with one pen and less wavy lines with another pen (SP5 digitizer). The waviness is a result of the interaction between the digitizer, the pen, and the firmware that interpolates the pen position.
     
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  4. Qyygle

    Qyygle Pen Pal - Newbie

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    Hey Ricarva, haven't been paying a lot of attention to the forums, but I posted a reply to your comment on the lenovo forum too. I've switched over to using a lenovo active pen, which has resolved some of my jitter issues. The original jitter the screenshot on the lenovo forum was definitely a hardware problem however, I went to best buy and traded the device, the new one does not show that extreme jagged jitter.

    I'm not sure about the jitter in your screenshot however, it doesn't look like the hardware failure issue on my original c940. Do you draw with a glove, or do you prefer bare hands? Sometimes it seems the AES palm rejection still allows slight input from the hand itself while drawing, n-trig has been doing better with this on recent iterations.
    Another thing you might want to try is reseating the stylus tip, (use a tweezers or just your fingers, pull off the tip and firmly put it back in) I had a bent tip on my stylus a little while ago and it made my linework randomly go crazy until I noticed and replaced it.
    Finally, if you're using a lenovo pro pen or the wacom bamboo ink plus, anything that supports tilt, I notice a lot more jitter on those pens. The C940 does support tilt functionality, but I think AES's implementation is causing a lot more pen jitter for normal tracking as well. I had bought a ink plus, thinking it might be better than the normal ink which I was originally using, but it was so much worse with diagonal wave and jitter. After the Ink I was using broke, I bought a lenovo active pen 2, which is working well right now.

    In regards to the questions on grid density, I agree with ATIVQ. Higher grid density certainly should allow for greater accuracy, but the firmware, pen polling rate, and implementation by manufacturer have just as great impacts on the outcome.
     
  5. ricarva

    ricarva Pen Pal - Newbie

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    Thanks for the reply, @Qyygle

    All of the lines in my capture were done with my hand off the screen.

    Where did you get the extra tips? There were none included with my C940. One thing I did get initially was that the pen tip seemed to get stuck and that resulted in "phantom touches"; reseating the tip made that go away, albeit temporarily - probably another issue to chase with tech support after this one is done.

    For what it's worth, local Lenovo tech support has decided to swap out my whole LCD module plus the internal connection cables. While I'm not thrilled to have surgery done on a brand new machine, I'm curious to see what - if any - impact this will have on the issue at hand.
     
  6. Qyygle

    Qyygle Pen Pal - Newbie

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    The tips from my old bamboo ink and the tips from the lenovo active pen 2 I am using were all interchangable with the integrated stylus.

    Good luck with the screen swap. Hope that goes well.
     
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  7. zendragon

    zendragon Scribbler - Standard Member

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    Not C940 related, but does anyone know if the pen pressure capability of the active pen vs active pen 2 is pen based or based on the device using it? I have an old miix 700 that my pen stopped working on. Getting a new active pen is only $25, but I'd be willing to spend more if upgrading to the pen 2 gave me a better experience.
     

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