View Full Version : Pencil In Rendered Mode = Artifacts
afxwinter 06-21-2007, 09:08 PM Anyone else notice that using a pencil tool with a Rendered dab type gives really weird results like these:
http://home.cogeco.ca/%7Emblack4/cg/PainterArtifacts.jpg
What causes this to happen?
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rattsang
06-21-2007, 11:32 PM
this is due to using the rendered dab type at anything less than 100% opacity- it usually happens at sharp turns but can happen with slight angles to a lesser extent as well, the only way to get rid of it is to use 100% opacity ( but then it wont be a pencil brush but a pen) as far as i'm concerned these artifacts are a bug with the rendered brush type- i don't know what corels offical stance on it is but ppl are always mentioning it as a bug, there is no known work around.
just use a differnt dab type build up or cover works best for me.
good luck
rat
Jinbrown
06-21-2007, 11:55 PM
afxwinter,
That happens with the Pattern Pens' Pattern Pen variant too (it uses Dab Type: Rendered, as do several other brush variants). Take a look at these examples done in Painter 6 and read the text below the images. Maybe they'll make you smile while you're figuring out how come this happens and what to do about it. ;)
Pattern Pen Porpoises, Gabby Grubs, Babbling Balloons, or Who? (http://www.pixelalley.com/brushstrokes/brushstrokes-pg1.html)
Or... Making Lemonade Out of a Lemon (http://www.pixelalley.com/brushstrokes/brushstrokes-pg11.html)
I find the best way to control those "artifacts" is to paint with a light pressure and make the strokes in a sweeping movement with no sudden, sharp turns. If you hesitate, press too hard, or make a sharp turn the brush dab will start to spin and leave more paint.
To see the spin "up close":
Try making the brush size about 150, open a medium-large white Canvas, choose black as the Main Color, then place your cursor in the center of the Canvas and press just a little to encourage the dab to spin. If it doesn't spin, move it around in a tiny, tiny circle until it does, like this:
http://www.pixelalley.com/tips_and_tuts/rendered_spins.jpg
Just curious, why are you working with a Pencil variant with the Dab Type set to Rendered? None of the Pencils' variants in the default Painter Brushes brush library use that Dab Type so I figure you must have changed it.
If you want a pencil stroke, use the Pencils' variants in their default state, or with minimal adjustments that won't change the entire character of the stroke.
That's my suggestion, anyway. You may have some compelling reason to use Dab Type: Rendered.
I haven't given you a very technical answer, but maybe this will help you understand how Rendered Dab Type variants work.
Where's John Derry when we need him? ;)
rattsang,
Buildup and Cover aren't Dab Types. They're Method options.
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afxwinter
06-22-2007, 01:28 PM
Thanks for the responses!
The reason I was using the rendered dab type is because I read 'in the manual i believe' that the rendered type is superior to circular since circular is simply a circle repeated over and over and rendered is SUPPOSEDLY perfectly smooth. I'm new to Painter so there's a slight learning curve coming from photoshop. :)
Jinbrown
06-23-2007, 07:03 AM
Thanks for sharing your reason for choosing Dab Type: Rendered. That helps us to know what you want so maybe we can help better.
It's true that brush strokes painted with a variant that uses Dab Type:Rendered are generally smoother but not true they're generally superior to strokes painted with variants that use other Dab Types.
It all depends on the look you want and how the brush variant is used.
The Pens' Scratchboard Tool also uses Dab Type: Rendered and strokes painted with this variant can appear entirely smooth and without the artifacts we've been talking about, if it's used at a small enough brush size:
http://www.pixelalley.com/tips_and_tuts/scratchboard_tool_2_sizes.jpg
I recorded the left stroke, then increased the brush size and clicked on the Canvas to apply the right stroke. In the left stroke, where I began the stroke, my hand was slightly shaky so you see that wobble in the stroke. Also, as I was applying very light pressure, when you zoom in close you'll see the beginning of the stroke is all anti-aliasing (no black pixels) and in other parts of the stroke where it's very narrow, there's only one black pixel with anti-aliasing on either side so the stroke begins to look a little "flaky" even at 100% zoom (which is what you see above). The problems in the right stroke are very obvious, the start of a "spin" at the beginning and lots of lumpiness along the edges in the rest of the stroke.
Here's another demo but this time with the Pencils' Cover Pencil which is a dab based variant and uses Method: Cover and Subcategory: Grainy Soft Cover. Notice the round overlapping dabs are visible in the right brush stroke where less pressure was applied and the Opacity is lowered, and even along the edges where more pressure was applied and Opacity is higher:
http://www.pixelalley.com/tips_and_tuts/pencils_cover_pencil_2_sizes.jpg
I changed the Subcategory from Grainy Soft Cover to Soft Cover to get the smoothest possible stroke with the brush size at 10.0. At this size (10.0) the overlapping dabs aren't visible but at size 100.0, to make them not appear, we can adjust Spacing to 1%.
In the demo below I adjusted Spacing to 1% for both the left and right brush strokes:
http://www.pixelalley.com/tips_and_tuts/pencils_cover_pencil_2_sizes_02.jpg
While there's still some lumpiness along the edges of the size 100.0 stroke, it's much less evident than in the first image above, using the Dab Type: Rendered. It's always possible some of that is due to my hand shaking just a bit. You'd have to try it yourself to see how it goes, but this is the combination of settings, of all of the ones demonstrated in this post, that I'd use to get smooth, anti-aliased brush strokes.
If you want your brush stroke to interact with Paper texture you can change the Subcategory to Grainy Hard Cover and adjust the Grain slider:
http://www.pixelalley.com/tips_and_tuts/pencils_cover_pencil_2_sizes_03.jpg
The result will vary depending on the selected Paper texture. Here I used a Paper from the Painter IX CD, named B_Purple_Pink. I don't remember which Papers library it's in as I've got it in a custom Papers library now. Also, I don't know if it's on the Painter X CD as well, but here's a screen print to give you an idea of how this Paper looks so if you like it and don't have it, you might be able to find something similar or create something similar:
http://www.pixelalley.com/tips_and_tuts/B_Purple_Pink_scrnprnt.jpg
Painter X screen prints are © 2006 Corel Corporation, reprinted by permission.
There's lots more, obviously, that we can do to adjust brush variants to make them work the way we want but this should give you a start, and some ideas for adjusting other brush variants.
Cheers!
afxwinter
06-27-2007, 02:53 PM
Thanks for taking the time to respond Jinny, that post has enough info for me to better decide which variant to use when sketching in Painter!
Jinbrown
06-27-2007, 11:12 PM
Hi afxwinter,
You're welcome!
Remember not to limit yourself to brush variants from the Pencils and Pens categories only.
In Painter, the brush category names only indicate the kinds of traditional media they can be used simulate but Painter artists often use variants from unexpected categories.
For instance:
Airbrushes' variants or Pastels variants to paint "washes" for watercolor skies.
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