topic Re: True line weight vs Hairline display: not coherent view in Project data & BIM

True line weight vs Hairline display: not coherent view

dfks — Wed, 03 Dec 2025 08:30:16 GMT

Hi,

I made a section that looks amazing with the Hairline turned on (True Line Weight off): contour thicker and the inside very thin.
When I set the True Line on, it looks really bad and doesn't follow any drawing rules.

Do you know what could it be the setting that makes the difference?

Re: True line weight vs Hairline display: not coherent view

Karel Landa — Fri, 28 Nov 2025 12:26:28 GMT

I can't give you a full advice since I don't know how you use your pen set.

BUt one solution could be to combine two view on the layout.
One view, where everything is with thin lince = edit pen set for the view so that all lines are only thin (e.g. 0,08 mm)

Second view, where with use of Graphic overrides, cutted parts will have transparent background and and separation lines between materials turned of, Lines thick.

Then you can combine it.

Although in czech, here is a manual on youtube

Re: True line weight vs Hairline display: not coherent view

Benedek Gaszpor — Wed, 03 Dec 2025 01:08:47 GMT

You can also check the Section or Elevation settings, where you can override the cut and non-cut elements appearance.
Thus you can assign a consistent cut contour line pen (1) with a thicker weight, and a fine line for everything else (2).
And if you feel especially tricky, you can even spice it up by turning on the depth separation and assign an extra visual layer on top this (3).
Just by playing around in the Section / Elevation tool settings.
Although, keep in mind that the Graphic Overrides and MVO settings will always overpower these.

Hope it can help. 🙂
Cheers!

Re: True line weight vs Hairline display: not coherent view

Barry Kelly — Sat, 29 Nov 2025 05:20:34 GMT

Can you show some images please?

The pen set you use needs to be set up to use the pen thicknesses that you want to print.

The line thickness is always centred the the hairline (centre) of the line.

Yes, they can look pretty ordinary on screen, especially when you zoom in.

But if the pens are set to the thicknesses that you want them to print, all should be OK.

Unless you print in hairline as well then the pen thicknesses don't really matter, but you normally wouldn't print in hairline.

Barry.

Re: True line weight vs Hairline display: not coherent view

dfks — Tue, 02 Dec 2025 08:30:34 GMT

Hi all and thanks for the feedbacks.

The problem doesn't actually lie in the pen sets. I generally use two thickness: 0,1 For the lines and the hatches, 0,2 for the Sections and they are actually right displayed in the screenshots above. Moreover, the settings in the attached - as @Benedek Gaszpor pointed out - are also good and the behavior right.

The real issue is the merging of two elements, such as the wall and the ceiling. The section line should ignore the thickness where the joint is and keep on running just on the contour, as also all the elements are being treated with SO. This is correctly shown in the "Hairline" mode.
But when the thickness is turned on, the thick line keeps on running through the element.

Maybe is something related with the configuration of material/layer priorities?
In order to achieve the complex profile connection, for instance, the elements should lay on the same priority level but with different material priority. This is anyway not really possibile in the building I'm drawing, since the complexity of the operations and the phasing of the construction doesn't help: the building is under renovation and the renovation filter are unfortunately anything but enough.

And indeed if the walls lays on the same layer and is made with the same material, the section works again fine. But why should by design the section not following the general drawing rules also with two different materials?

Re: True line weight vs Hairline display: not coherent view

Benedek Gaszpor — Wed, 03 Dec 2025 12:32:16 GMT

Hi @dfks ,

Thanks for the clarification.

Now this might not be the source of your issue, but similar problems can be caused when the elements are on separate layers and the layers connection class is different.
If the layer intersection group number is different between two layers, the elements will not "intersect" with each other among the two layers.

If the layer intersection group number is set to "0", it will not even intersect among the elements on the same layer.

This can be powerful sometimes, since you can lighten up the computer's calculations load when generating a view, but frustrating as well, when random lines appear, where there should be none.

The other thing that you have mentions already is the renovation status of the separate elements and their visibility settings on the renovations panel.

But if I gather it correctly from your comment, you have already gone through that...

If you are using AC26+ you might try to play around with the Design Options as well, if the renovations feature is already depleted... Although if you are already far along the project that might be a huge undertaking...

Maybe @Barry Kelly, has some better ideas and more insight.

Cheers!

Re: True line weight vs Hairline display: not coherent view

Barry Kelly — Wed, 03 Dec 2025 12:33:15 GMT

The line thickness is centred on the hair line and the ends are always round and extend beyond the node by half of the thickness.

In hairline you don't see this.

But with true line weight you do.

These are exactly the same lines as the hairline ones above, just with thickness turned on.

The thicker the line, the worse it looks.

And the more you zoom in, the more you notice it.

A line drawn first will be under a line drawn second, but depending on the thickness may or may not hide the line below.

The thicker line will always be seen and will not be cut off.

You can use display order to bring forward send back, but the thick line will always be seen.

It gets more complicated when you start using white lines (they won't print) or fills with or without perimeter lines.

Again the same lines as above with the fill brought forward.

Your composites use building materials which use fills, so will end up looking like this.

Generally when you are printing with true line weight, a thick pen representing the building elements will probably be only 0.5mm thick?

No matter what scale the drawing is.

At least in my experience.

Apart from page border lines and title block or note borders, they may be a little thicker.

Your printed plans should look OK unless you are using very thick pens.

Remember on screen you can zoom right in and that is when it looks bad.

I am not sure if this helps or not.

Barry.

Re: True line weight vs Hairline display: not coherent view

dfks — Tue, 02 Dec 2025 09:50:04 GMT

Hi,

that's exactly what I mean. But with this logic I should draw everything on one layer, with 1 priority and with the same material.

What it's not clear to me is why archicad makes the calculation in the right way without the thickness but then doesn't take into account it when the true line weight is turned on.

Re: True line weight vs Hairline display: not coherent view

Benedek Gaszpor — Wed, 03 Dec 2025 12:35:18 GMT

Hello @dfks ,

Not necessarily.

When you are using the layers, just keep in mind that if you wish the elements to intersect (and the computer to calculate with it), those layers are on the same connection class number.

Of course, the building material issue can still be relevant then, since the fills will only merge visually if the building materials are the same, and the stronger material will cut the weaker one (unless you do some extra wizardry with some solid element operations...).

Check the active layer combination assigned to your section view.

The saved layer combinations also store the layer intersection group number, not just the visibility and locked status.

Another thing that just popped into my mind... although it might be way off, and you are probably already familiar with it, just in case:

It is best practice to assign saved view settings to all of your views.

Assigning a defined Layer combination, Pen set, MVO, Graphic override, and Renovation filter.

And do not keep stuff as "Custom". (As you see on the attached image.)

It is bad practice; it can mess up your workflow, and in some cases, can even result in some bugs or mishaps that take a lot of time to figure out and fix.

Hope this helps 🙂
Cheers!

Re: True line weight vs Hairline display: not coherent view

dfks — Wed, 03 Dec 2025 08:33:23 GMT

Hi,

thanks to all for the replies. I just realized that in my first post the screenshot were not uploaded (sorry @Barry Kelly). I uploaded them now.

@Benedek Gaszpor sure, but also this is not my case since I'm basically working just with saved views and layer combination.

Re: True line weight vs Hairline display: not coherent view

Benedek Gaszpor — Wed, 03 Dec 2025 12:37:51 GMT

Hm... In that case, it is most likely the building material issue, in my opinion.

If the two elements have different building materials, even if the section fill is exactly the same, there will be a line between the two.

Oh... I've just noticed something:

On your first image, that's not really hairline visualization, but "Bold Cut Lines".

As I remember correctly, with the basic Archicad settings, when you turn off the "True Line Weight," it defaults to "Bold Cut Lines" on.

If you really wish to see a true hairline for editing, you need both the "Bold Cut Lines" and the "True Line Weight" option off.

Bear in mind that this is only an On-screen view option and will not modify the end result when plotted.

For the end result, it will always plot it by using the True Line Weight.

(Unless you override it for the plotting settings, to plot everything as a hairline. But alas, the desired, stringer outlines are still missing.)

In this image, you can see the logic of how it works:

And here is where you can toggle it:

So If you wish to get an end result, where the perimeter lines plotted as thicker, while keeping the other lines as is:

1) You can make sure that the elments have the same building material, thus the line in between them will be invisible, as the fill patterns will merge.

2) You go the manual way and draw the thicker outlines on top manually. 😕

Hope this helps, or gets you closer to the desired end result. 🙂

Cheers!