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.
- linetypes-modelspace.png (4.8 KiB) Viewed 11034 times
If we view this with "Screenbased-linetypes" it is almost the same
- linetypes-modelspace-screenbased.png (5.76 KiB) Viewed 11034 times
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
- linetypes-NOT-scalewithviewport.png (11.19 KiB) Viewed 11034 times
Exported to PDF this will look like this
- linetypes-NOT-scalewithviewport-printpdf.png (18.03 KiB) Viewed 11034 times
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:
- linetypes-scalewithviewport.png (11.21 KiB) Viewed 11034 times
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
- linetypes-scalewithviewport-printpdf.png (13.8 KiB) Viewed 11034 times
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
- linetypes-modelspace-0.1-scale.png (5.38 KiB) Viewed 11034 times
With this scaling we are no longer able to see the individual gaps in the line. However ...the paper space looks as expected
- linetypes-NOT-scalewithviewport-0.1-scale.png (11.16 KiB) Viewed 11034 times
whish is also reflected in the resulting PDF
- linetypes-NOT-scalewithviewport-0.1-scale-printpdf.png (18.49 KiB) Viewed 11034 times
If we now again check the
"Scale of linetypes matches the scale of the viewport" The paper space will become
- linetypes-scalewithviewport-0.1-scale.png (11.07 KiB) Viewed 11034 times
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!
