topic Re: Visual Artifacts when Publishing PDFs in Documentation

Visual Artefacts when Publishing PDFs

hevi — Tue, 28 Jun 2022 13:38:13 GMT

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.

Re: Visual Artifacts when Publishing PDFs

hevi — Tue, 21 Jun 2022 08:57:20 GMT

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.

Re: Visual Artifacts when Publishing PDFs

hevi — Tue, 28 Jun 2022 06:46:43 GMT

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

Re: Visual Artifacts when Publishing PDFs

Lingwisyer — Tue, 28 Jun 2022 07:27:33 GMT

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.

Re: Visual Artifacts when Publishing PDFs

Barry Kelly — Tue, 28 Jun 2022 07:58:40 GMT

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.

Re: Visual Artifacts when Publishing PDFs

Lingwisyer — Tue, 28 Jun 2022 08:13:44 GMT

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

Re: Visual Artifacts when Publishing PDFs

Barry Kelly — Tue, 28 Jun 2022 08:46:36 GMT

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.

Re: Visual Artifacts when Publishing PDFs

hevi — Tue, 28 Jun 2022 13:34:41 GMT

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.

Re: Visual Artifacts when Publishing PDFs

hevi — Tue, 28 Jun 2022 11:53:36 GMT

@hevi 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.

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

Re: Visual Artifacts when Publishing PDFs

hevi — Tue, 28 Jun 2022 13:26:39 GMT

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).

Re: Visual Artefacts when Publishing PDFs

hevi — Tue, 28 Jun 2022 19:49:13 GMT

To sum up:

These issues seem to ultimately be caused by the fact that AC splits fills into segments when publishing or printing to PDF which present issues related to anti-aliasing when the PDF reader renders solid fills with shared boundaries. In addition publisher creates a cliping mask for vectorial/symbol fills which causes the lines to be clipped and incorrectly displayed in PDFs.

@Minh Nguyen It would be interesting to hear GSs thoughts on this. I guess that it is a rather tricky thing to get right.

These are the fixes I've found to work.

For opaque solid fills - go through the render settings of the PDF reader. For Adobe turning off 'Smooth line art' seem to fix it but at the cost of increased aliasing.

For transparent solid fills. Reprint the PDF with flattened transparency, eg. using Adobe PDF as printer.

For vectorial/symbol fills. Print to PDF instead of publishing or edit the PDF to remove the clipping mask.

Re: Visual Artefacts when Publishing PDFs

Minh Nguyen — Wed, 29 Jun 2022 10:20:39 GMT

Hello,

Thank you very much for sharing your thoughts and experience with this issue!

I'm wondering when you print out the PDF to paper, will it be visible on the printed sheet?

As far as I know, indeed this happens due to PDF Reader's algorithm. At certain zoom, these artifacts maybe visible or maybe not, but from our experience, the issue won't show up on the prints. Could you please confirm it?

Best regards,

Minh

Re: Visual Artefacts when Publishing PDFs

hevi — Fri, 01 Jul 2022 09:17:20 GMT

Yes, most cases print to paper without reproducing the artefacts but I guess that ultimately depends on the printer setup just as with monitors.

But the question is - should we have to live with these issues for PDF drawings? A format that is widely used for presentations where we actually care about more than informative content of the drawing. A format which, being vector, encourages the use of zoom. Should I really have to choose between jagged lines or fill artefacts (given that the one viewing it even knows how to control that)? Should I really have to go though post-publish processes to get a clean presentation of a simple nature?

I understand that the implementation of a solution probably is harder than its conception but: the ability to merge identical fills of intersecting objects would solve all three issues; the ability to flatten the transparency of fills would solve the shadow issue (but turning it into the solid fill issue) ; and the ability to publish vectoral/symbol fills only as lines would solve that issue.

Re: Visual Artefacts when Publishing PDFs

Minh Nguyen — Fri, 01 Jul 2022 12:05:06 GMT

Hello,

Thank you for the feedback, I totally understand the struggle caused by this issue. It also happened to me a few times. We had an existing about this (IDEA-3623), I already added your comment to this one. Hopefully, our Product Management team will consider adopting it in the near future.

Thank you once again for the detailed feedback, we really appreciate it!

Let me know if you have any further questions!

Best regards,

Minh

Re: Visual Artefacts when Publishing PDFs

Burcu Meral — Mon, 12 Sep 2022 14:46:17 GMT

Thank you so much for the answer. But turning off 'Smooth line art' increases aliasing just as you said. Is there no other solutions to fix the problem?

Re: Visual Artefacts when Publishing PDFs

hevi — Thu, 15 Sep 2022 09:07:17 GMT

@Burcu Meral I share the frustration from not being able to produce high quality presentation material from the standard workflow. My workaround for situations where I find these artefacts unacceptable is to create worksheet/drawing and use Fill Consolidation to merge identical adjoining fills - a functionality that I think should be integrated in the publish process.