QCad and linetypes drawing issues

[Maystor]

Hi,
Recent QCad doesn't draw correctly linetypes from Autocad generated files (dwg), no text on the line for example. Moreover, i cannot select with mouse polylines with particular linetypes, i don't know why.
Any help would be appreciated.

Keep the work.

Operating System : Fedora 39
QCad version : QCad Professional 3.29.3 (version Qt 5.14)

[CVH]

Recent QCad doesn't draw correctly linetypes from Autocad generated files (dwg),

Is that using Screen-based Linetypes or not?

no text on the line for example

Custom Linetypes or especially those that include shapes (=text) may not be displayed 'as-is' using Screen-based Linetypes.
This is to speed up the display rendering.
One can toggle that with:

• Menu View .. Screen-based Linetypes (NL)

• Using the related button on the View Toolbar

• With the keyboard shortcut 'NL', simply hit the 'N' key briefly followed by the 'L' key

Moreover, i cannot select with mouse polylines with particular linetypes, i don't know why.
Any help would be appreciated.

Please read the forum rules in red above.
Indicate your operating system and QCAD version.

Would it be possible to share such an example file, so that we can help you more specifically?

Regards,
CVH

[Maystor]

I've edited my post with informations.

I've ever tried to reload linetype definition with the right module and tried to deactivate/reactivate linetype for screen (NL) and it doesn't work.

The linetype list shows correctly lines, but not on the lines. See the capture.
I cannot select the colored lines (yellow for example) and do modifications. They have to be like in the linetype list in the right.

[CVH]

The linetype list shows correctly lines, but not on the lines. See the capture.

The capture also shows that Screen-based Linetypes are active.
Never seen a drop-down box before that spans the entire screen.

Please provide in the file seen in the capture.
And perhaps we need to verify the *.lin file(s) too.

If you don't want to share them on a public forum then please consider to attach them to a Private message (PM)

Regards,
CVH

[Husky]

Moreover, i cannot select with mouse polylines with particular linetypes, i don't know why.
Any help would be appreciated.

According to your description of the problem, I assume that the ACAD drawing was created in 3D. QCAD is 2D and would not be able to read 3D correctly.
Please try to flatten the drawing to 2D below:
Menu > Misc > Modify > Flatten Drawing to 2D
and try to select the "unselectable" lines again.

[Maystor]

Moreover, i cannot select with mouse polylines with particular linetypes, i don't know why.
Any help would be appreciated.

According to your description of the problem, I assume that the ACAD drawing was created in 3D. QCAD is 2D and would not be able to read 3D correctly.
Please try to flatten the drawing to 2D below:
Menu > Misc > Modify > Flatten Drawing to 2D
and try to select the "unselectable" lines again.

That gives the possibility to select the polylines which i can't previously. But it doesn't correct the draw of the polylines.

P.S. : my file DWG in the capture does not have, in theory, other type of element like 3D polylines. Previous version of QCad drawed correctly the lines.. I don't know when and why the problem begun.

[Husky]

<<Previous version of QCad drawed correctly the lines.. I don't know when and why the problem begun.><

Ok, one down (3D), more to go ...
Does the linetype exist in your current Qcad version or is it substituted? Does the Linetype shows correctly in "Print Preview"?

[Maystor]

No change in Print Preview.

[CVH]

QCAD is 2D and would not be able to read 3D correctly.

Husky, I have to disagree with how you put it.
QCAD methods for drawing new entities are basically limited to 2D, true, but QCAD reads and handles 3D information fairly correct.

There are exceptions. An arc for example can only exist in a flat plane and that is not necessarily limited to Z=zero.
But for straight entities or entities with straight edges there is nothing really wrong.
BTW: For standard arcs, circles and ellipses there are too few parameters to define them on a slanted plane.

In detail, QCAD/CAM relies vastly on 3D information meaning that QCAD resources can define, handle, read and write information in 3D.


As far as I know I can tweak a line endpoints or polyline vertices its Z parameters to be different than zero, even with all different values.
And then it is still highlighted or selected with a simple left-click, box selecting works too.

A line from (10, 10, -4) to (20, 15, 7) is reported to be 15.68438714 long what proves that there is nothing wrong with the Math.
Length = sqrt(10² + 5² +11²) = sqrt(246) = 15.684387141358121934184656475264

True, the length property will be incorrect for a polyline with bulges in 3D because QCAD can not handle the arc length in 3D.
An exception is reported while Save/Autosave that a 3D polyline with arc segments is flattened to 2D.

- - - - - - - -

For the Linetypes:
@ Maystor: We really need an example file to replicate the reported issue, a partial snippet is OK.
Copy only what we see in your capture and paste that to a new file, attach that snippet.

Linetypes don't necessarily need to be 'installed' under QCAD, the list of types in the active drawing is based on: Predefined + Drawing defined.

We see that the rendering is fine in the Linetypes drop-down box.
Remark that these previews are nothing else than short line segments formatted in the listed Linetype at a certain scale.
There is nothing like a preview image of a Linetype stored in *.lin files.

And then it could be that the scale in the drawing is off or that recent QCAD versions handle it different (faulty?).
But it can also be a CXF vs SHX issue.
Without an example file we are only guessing.


Regards,
CVH

[CVH]

@ Maystor:
I have received the file by PM.

It is not the 3D art of the polylines that makes it not possible to select them.
It is the combination of Z-5 and the custom width of 0.02 units.
BTW: A box select works when whole the polyline is inside the box.

For example L199, 'GAZ a Basse pression' the global Z is -5 and the Global Width is 0.02 ....
If we remove the Global Width by setting it to zero then all looks OK. (Not using Screen-based Linetypes)
I suspect that it is OR custom formatting, OR custom polyline Width.
AND seems to be formatted on custom width only.

Do not bother about Screen-based Linetypes or not because they are turned off by default for printing.
Toggling that in design mode will show them how they will be printed.

This works 'as is' with Lineweight 0.00mm but that may print far to faint on modern printers.
Altering the weight to 0.05mm and it may again look completely different.

Under Applications Preferences .. Graphics View .. Appearance .. Linetypes and Lineweigths
- One can select if types should be scaled on weight or not.
- If so, then weight 0.00mm would multiply by zero and to avoid that a replacement weight for scaling patterns can be defined.

My settings where YES and 0.25mm(ISO) what made it display OK once I cleared the custom width.
But using weight 0.05mm the Linetype is scaled by 0.05 instead of 0.25 ... The text and inter spacing is 5 times smaller.

Hoping that this sheds some light on the issue and that you can work out a best fit strategy.

Regards,
CVH

[Maystor]

Hi CVH,
Thanks for your help.
Effectively set polylines at 0 to Global Width to polylines let you to select and see the correct draw polylines... But any settings as you deviced to the global application doesn't help. I'm affraid that's not the best way for my condition.

[CVH]

Hi,
Simply don't mix: Z not zero .. & .. Custom polyline width .. & .. Custom Linetype.
Z not zero should be avoided in QCAD there not all drawing methods handle that very well.
Some rendering may be affected too like polyline arc segments with custom widths.

One can however use a custom Linetype and a predefined Lineweight.

Then remember that the Linetype data can be scaled by weight by preference or not.
And that one can not scale a type by zero (weight 0.00mm) as used in several places in your drawing.
Therefor it is possible to specify what weight and thus what scale to use for drawing art in Lineweight 0.00mm.

When scaling Linetype by weight is active:
- Weight 0.05mm means scale type data by factor 0.05 aka 20 times smaller
- Weight 0.35mm(ISO) means by factor 0.35 (~1/3)
- Weight 1.00mm(ISO) does not scale the predefined Linetype data
- Weight 0.00mm will fall back on the type specified in App.Prefs.

When inactive the predefined Linetype data is not affected by drawing art weights.

Remark that there is also an independent and cumulative Linetype Scale factor.

Specify a well suite zero replacement or use a different Lineweight not 0.00mm.
The closest non zero to 0.02 is 0.05 but that might scale your type by factor 0.05 when scaling is active.
In that case you can counteract factor 0.05 by Linetype Scale factor 20.

When using Blocks then Attribute inheritance may be involved (=General Properties) ...
... Experiment with that because I have no closed-form explanation on the actual behavior in all cases.

Bottom line:
There should be a work around but that might require altering specific entities properties.

Regards,
CVH