the preview of the stroke while holding the stylus

▲ the preview of the stroke while holding the stylus

after lifting (releasing) the stylus

▲ after lifting (releasing) the stylus

enter image description here

As you can see in the above images, after lifting (releasing) the stylus, the shape of the stroke immediately changed. This happens to both the brush tool and the blob brush tool. I have set the fidelity to the most accurate end.

I understand that vector drawing is different from bitmap editors, but if it can preview the shape, surely it can process and display the shape, right? If it really can't process the shape, no problem, just give me a preview of what it can process. I just want the preview to be the same as what I get.

Is there some setting to control this behavior, or is it an innate characteristic of Illustrator?

  • 1
    Double click on the tool to open up the smoothing options.
    – joojaa
    Feb 11 at 5:38
  • @joojaa Thanks for replying. As I said, I have set the fidelity to the most accurate end.
    – Betty
    Feb 11 at 6:01
  • yes but smoothing needs to be as low as possible too. And these settings are all you get no more options. If you want more then its time to make your own software (sorry that is how technology and law really works, even a tiny step more may mean a whole new investment effort with no piggybacking on others code) and consider not using a vector software.
    – joojaa
    Feb 11 at 6:49
  • @joojaa I mean, I can accept the smoothing, I just want to see what I get, or get what I see.
    – Betty
    Feb 11 at 8:12
  • Smoothing by definition is you dont get what you see. Because the smoothing can only be applied once everything is there.
    – joojaa
    Feb 11 at 12:30

The settings are counter-intuitive.

You want the Fidelity setting to be low, not high.

The devs are engineers.. in math a high fidelity means less accurate.. to common, non-engineers or non-physicists.. a high fidelity means more accurate...

I, personally, set the Fidelity to about 0.5-1px and the Smoothness to 1-2%.

I would also point out that brushes are not "precision" tools. They aren't designed to be 100% accurate in all instances. They are for painting. If you need precision, the Pen Tool is more appropriate. In addition, there's a jump from the low resolution screen preview to the actual vector paths. Paths may not always hit the exact pixel the preview may use. Much has to do with a screen's pixel density, the actual pixel grid for the document, any snap settings, etc. The exceptionally minute changes seen in your animation is well within traditional acceptable limits. In fact, I'd lean towards the changes merely being smoothing - as mentioned in the comments below the question. Again, don't use a brush if you want exact precision.

  • Its also not the only term that means different thing. Color temperature is also reversed in physics versus color temperature in art. And high quality does not mean superior product but a product that has a acceptable manufacturing failure rate, the product can still be crap. Also resolution and precision mean different things in engineering than in lay speak etc etc.
    – joojaa
    Feb 11 at 13:35
  • Thank you for replying. However, what you describe is actually older versions of AI. The recent versions have removed the Smoothness option and there is only one Fidelity option now. (See static.vecteezy.com/system/assets/asset_files/000/000/861/…) Also thank you for mentioning other possibilities like snap settings. Now it seems that even with all settings right, there will still be a discrepancy between the preview and the actual result. I just wanted to make sure it is so and not that I missed some settings. :)
    – Betty
    Feb 12 at 0:20

It's because what you are seeing is merely a low resolution preview of the brush.

The actual brush isn't applied to the path until you lift the stylus. There's no way to change this behaviour in Illustrator's brush tool. It will always apply some level of smoothing after you release the stylus, even with the fidelity set all the way to accurate.

Perhaps if you want that exact kind of control, use a raster image editor like Photoshop where you can actually see the pixels as you paint them.

Here's an example in Photoshop using the Brush tool. Ignore the slightly offset pixelated brush cursor here since my screen recording software doesn't record it properly.

enter image description here

Here's another using the Pencil Tool in Photoshop, which would be ideal if you want that pixelated/non-antialiased look.

enter image description here

  • Thanks. So it is indeed can't be changed. Just thought there's no harm in asking. :)
    – Betty
    Feb 12 at 0:10

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