[SOLVED] Display lines as solid, but print as dashed?

[danbr]

I have a large, complex drawing; 4.5Mb and about 1400 entities. There is a separate thread here: https://qcad.org/rsforum/viewtopic.php?f=33&t=7861 which discusses how to simplify that drawing so that the performance is acceptable (thanks, @CVH!).

One of those simplifications was to change the line type for the majority of the drawing elements from ISO DASH to Continuous. However, the current image is basically "background"; I need to add my own information on top of it. If the lines are dashed (and my own content is not), it's quite clear what the intent is on the printed document.

Ideally, there would be a way for the displayed lines to remain continuous so that QCAD doesn't have to render all those dashes, but for the lines to print as dashed.

Any ideas? Or did I miss this in the documentation?

Thanks!

Dan

[CVH]

Hi, again

The dashes aren't really an issue until you look closer at them.
I am also figuring that out at the moment.
QCAD has not really an issue with dashes but the gain of using continuous was obvious.
Not long after that, I discovered the degree issue.
Not all degree 5 splines are an issue, reverting 1 certain back from 3-5 induced lagging of about 1-2fps.

>> In Model_Space I work with Screen_Based Lineypes (AppPrefs..Graphics View)

What I discovered in your original drawing seemed as the dash spacing was inverse proportionally to the controlpoint spacing.
At some points ... but there counter indications too.
And again it is not ... It swaps at a certain point ... adjacent splines with fairly the same spacing look rather different while zooming in on them.
As said, I am still figuring that out while writing.

Clearing Screen_Based Lineypes revealed other strange behaviors.
Like a Line entity is dashed and a spline is full,
- even with larger controlpoint spacing.
- even zooming in on it endlessly ....

Spline rendering was also off: in Screen_Based Lineypes it is jagged, off this is not.
But then you get all the different weights looking very odd.
In draft mode the view of all layers looses entities.
Didn't even tried the Anti-Aliasing.

On top speed is related too, simply turning off Screen_Based Lineypes set me on hold for 10-15 seconds.

All this made me to try out setting all things continuous.
Perhaps it is not even necessary to do so.
One of the reasons I use revisions instead of overwriting files.

For your foreground-background problem I use light and dark colors.
Very fine lines too. It is workable and it looks good on paper too.
Easier as finding individual good setting for the dashes.

Besides, I find that it looks messy... quickly.

Regards,
CVH

[CVH]

Before anyone starts to argue about what I listed on my findings...

Original drawing: roof_new.dxf
Clear AutoSave.
Set Sreen Based Linetype.

TH, enter 'bc17' OK
Between index 19 & 20 the dash spacing changes.
Clear Sreen Based Linetype. Wait long.
Line is full even in zoomState 0.001<0.01

Set Sreen Based Linetype. Short delay.
TH, enter 'bc25' OK
ZS & zoom a little out ... Line entity vs spline dashing!
Zoom in on one of the line endpoints >> dashing is about the same!?
In this zoomState Clear Sreen Based Linetype. Wait long.
>> dashing is still about the same

YW & Wait very long. (Thaw All)

TH, enter 'a4a2' OK
ZS
TH, enter 'a4a5' OK
Both are dashed and have a nice curl.
Set Sreen Based Linetype.
'a4a5' is still dashed but with a jagged curl, 'a4a2' turned full.
Zoom in on the curl of 'a4a5'
Hover and the entity gets the focus when on the actual curl and not on the 'short cuttings'

TH, enter 'bd5e' OK
ZS
Zoom in on the left side of it @(188,66)
Odd shape!
Zoom in and zoom out and see the dashing of some neighbors change.
Clear Sreen Based Linetype. Wait very long.
The odd shape stays (not jagged) the spline has different dashing, several others alter shape.

There are numerous of such examples in the file.

This took about 15 min, if can one spare the time:
Repeat this with different Linetype scales.

Regards,
CVH

[planksworkshop]

I too see strange behaviour between lines and splines dash spacing and much more. This reminds me of an exported Rhino drawing. I selected all the splines and changed all to 3 degrees. Yes they were varied but not enough to change the looks except for production. The file still takes time to load but once loaded is quick with dashed lines intact for printing. I would be interested if printing looks good though as on screen looks......odd.

[CVH]

I too see strange

Thanks, to at least acknowledge these things.

No, the dashes should not matter but there was some gain.

interested if printing looks good

That's a different story.
Printer? Laser? Size?
That relies on finding/setting (individual) good settings for all the Linetypes.

A year ago we changed to a desktop MFP laser and I didn't configure those settings anew yet.
Old drawings not using the color/size workaround are barely readable at some points ...
Fatter lines give wider dashing ....

Regards,
CVH

[Husky]

Hi Dan

Ideally, there would be a way for the displayed lines to remain continuous so that QCAD doesn't have to render all those dashes, but for the lines to print as dashed.

I don't expect a big performance drop with changing the layer attributes from continuous to dashed (5x). And yes - you can set QCAD still to Draft mode to have all lines on the monitor continuous but I doubt that that is necessary ...

Husky-2020.12.03-06.png (199.09 KiB) Viewed 8929 times

If used as a background and it is still to dominant you can change the color to a very light gray.

Husky-2020.12.03-05.png (118.91 KiB) Viewed 8929 times

Question: Will you print out of Model_Space or out of Paper_Space? Your Paper_Space looks bad and is much more responsible for a performance issue than your dashed entities. I don't know how you like to print it but it looks like your Paper_Space could use a little clean up ...

[CVH]

Sorry Husky:

to dashed (5x).

read:
https://qcad.org/rsforum/viewtopic.php? ... 861#p30646
>> 1408 exceptions on LineType. (~25%)

CVH

[danbr]

Thanks VERY much for the detailed investigation!!

I modified all the splines as suggested and changed the linetypes to all continuous (and I had already made them 0.05mm and light grey . Performance is fine now, so I can continue with my design work.

But that doesn't solve the problems of all those "exceptions on LineType" errors - how do I see those?

As an FYI, the original drawing was done by Ford using (apparently) I-DEAS or one of it's children

[CVH]

Nothing to worry.
The layer was set to dashed, 1408 entities had their own linetype property set to dashed too.
The doubling up for so many is a bit strange.
There was also 'ISO dash' + 'ISO dash space'.

The general idea should be that these properties are controlled by the Layer setting.
Not that exceptions can be needed or are by preference.

Many other individual properties equal the or differ from the layers settings too.

We got it working, that is the major thing.
The little difference between degree 5 and 3 is hardly noticeable with so much control points.
Sure, they are not/never exactly the same ...
You can find that it differs more with major curvature change and a low controlpoint count.

The origin would be a time-saver ... Rather common for automotive industry.

Regards,
CVH