How do I get dashed lines to show dashed in PDF?

[CerpherJoe]

Hello,

I have completed a drawing at 1:20 (1" = 20’) scale with some dashed lines. I notice in the drawing itself you can toggle ‘Screen-based Linetypes’. I have them toggled on and the dashed lines show up fine in Print Preview. However, they disappear when exporting to PDF. I have other test drawings (using various drawing units, but same 1:20 scale) where the dashed lines have printed fine in PDF.

Any ideas?

Thanks!

[Husky]

Hi,

there are three styles of dashed lines - do you have the same issue with each of them?

I have completed a drawing at 1:20 (1" = 20’)

Something doesn’t ends up with this scale statement
1:20 is not 1"=20’
Please doublecheck and tell me which one is used so that I can try to reproduce the issue on my end. BTW: A posted example drawing would make it easier for us to look into the issue …

[CerpherJoe]

Of course - you are right! Used 1:240 scale.

The dashed line I am using is ‘ISO Long-dash double-dot’.

I see many dashed line choices from the Layer->Linetype dropdown.
Jefferson Street NE LT2181778.pdf (108 KB)
Jefferson Street NE LT2181778.dxf (188 KB)

[Husky]

The dashed line I am using is ‘ISO Long-dash double-dot’.

I used the layer “Plat” which has that line type. PDF and paper print looks good to me. Is your print differed?

[CerpherJoe]

Thanks. No, I’m still having the problem.

Here’s from the PDF:

Here’s from QCAD:

[Husky]

Please try to open this pdf with a different pdf reader to see what happens.


Edit:
This is my test pdf produced by QCAD. Looks and prints just fine on my system.

test.pdf (3.61 KB)

[johan162]

This is something I have also found a bit confusing. The following is perhaps not so much a direct answer but some insights (or lack of …) in regards to line-type scaling.

My understanding of how it is supposed to work is illustrated below with a simple centerline pattern and how it appears in model-space, print-space and print-space and cahnges depending on viewport setting and linetype-scale setting. All images scaled to the same apparent screen size (roughly).

If we start with a linetype-scale of 1 (default) the model space looks like this.

If we view this with “Screenbased-linetypes” it is almost the same

If we then disable sceenbased-linetypes and put this in the paper-space in both a 1:1 and a 1:4 scale it will look like below

Exported to PDF this will look like this

If we instead repeat the previous exercise but with the option “Scale of linetypes matches the scale of the viewport” checked (Preferences->General->Linetypes) we get the following (the model space is not affected by this!)

Paper-space:

As we can see the 1:1 viewport is the same but the 1:4 viewport has been adjusted. In PDF it looks like expected

Changing the linetype-scale
In prints I prefer to have more tight lines so I usually apply a factor to the linetype scale and here things become interesting. The model space and print space does seem to start behaving in what might seem different ways. If we apply a 1/10 scale factor (0.1) the result is as follows:

First the model space

With this scaling we are no longer able to see the individual gaps in the line. However …the paper space looks as expected

whish is also reflected in the resulting PDF

If we now again check the “Scale of linetypes matches the scale of the viewport” The paper space will become

This result is unexpected. With the default linetype scaling of 1 the (1:4) scale in the previous example got a bit denser (don’t think it was four times though) bu he we actually get a less denser line! Which I cannot quite explain. My understanding of viewport scaling of linetypes is that the should follow the scale to appear the same in absolute appearance which clearly is a wrong understanding o my part..

My understanding was that the dashed lines should follow ISO absolute lengths However the above experiment shows this not quite to be the case since the model-space and print-space with the same 1:1 scale shows different density for the dashed lines. The print space (for center-line) shows a gap of 20mm while the model space shows a gap of ~0.6mm .

I’m sure I must have misunderstood something and since I can always workaround by manually setting a linetype-scale (to get the proper ISO spacing in the final PDF output I’ve just put this as on of life’s (many) mysteries!