Visual Artefacts when Publishing PDFs

[thesleepofreason]

When publishing PDFs I get visual artefacts in fills of intersecting elements. What I expect to be a continuous fill gets segmentet causing tears.

The effect is admittedly small but still noticeable even at normal zoom levels - especially for solid fills and thus makes digital drawings look sloppy.

Is there a way to avoid this when publishing? I does not occur when printing the layout using Adobe PDF so technically, it should be possible.

[thesleepofreason]

In elevations I get a similar artifact when shadow fill covers two connected walls. Here it is even more noticeable and actually a real issue. 

The vertical line in the image is from a wall that has been split into two. 

[thesleepofreason]

So no response on this. Am I alone in getting these artifacts or is it just me being a stickler?

[Lingwisyer]

Would guess that this is due to how AC is intersecting the walls? When you add skins to all of your walls I find you get more off these ghost lines. Pretty sure it is also not just limited to shadowed areas, just they have higher contrast and hence are more noticeable. Have your tried changing the junction order of the relevant walls? Some other order might clean up properly?

Ling.

[Barry Kelly]

I have no idea about you PDF artefacts, but the shadow you show here is a legitimate shadow.

It is not some kind of artefact.

Barry.

[Lingwisyer]

He's talking about the grey vertical line on the left, at the 4th rafter.

[Barry Kelly]

Ah, I can only just see that now that you mention it.

I should have read the post properly!

I just split the wall and published as PDF.

There is definitely nothing to see in Archicad 3D or elevation, but there is in the PDF - but only when I zoom in to 150% or more.

Barry.

[thesleepofreason]

Alright, so I guess it is a common issue and that people live with it? Perhaps the effect has to do with monitor and reader settings as well. Below is a plan with solid black fill 1:100 viewed at 100%. I personally find this annoying enough to warrant some attention.

When publishing to PDF AC splits adjoining fills into segments based on elements. Eg. for two walls joining as above the corner is bisected into two segments.

The problem is that PDF readers have a hard time rendering adjacent fills correctly thus producing these artefacts. For solid fills the resulting artefact is the appearance of a off-color line at the boundary between two fill segments. At some zoom values the artefact disappears or decrease.

For vectorial/symbol fills the issue doesn't have to do with limitation of the PDF reader. Here the publisher creates line segments for the fill pattern that stretches to the boundary of the fill and then apply a clipping mask at the same boundary. The resulting artefact is that lines are clipped, see first post. Print to PDF does not create clipping mask but there might still be issues with the display order if the background fill is opaque.

[thesleepofreason]

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@thesleepofreason wrote:

Alright, so I guess it is a common issue and that people live with it? Perhaps the effect has to do with monitor and reader settings as well.

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After going through the setting in Adobe Acrobat turning off 'Smooth line art' seem to help with the issue of solid fills.

[thesleepofreason]

The issue with shadows is actually a bit different. The shadow fills are transparent and what happens is that they get displayed on top of each at the boundary - resulting in a darker color. The reason for this is beyond my technical knowledge but it seem to be connected to anti-aliasing and thus resolution?

It can be corrected by flattened transparency. So for example a published PDF with these artefacts can be corrected by reprinting it with adobe pdf (which flattens transparency).