QCAD.org Forum

I'm coming across repetitive patterns that require extensive mirroring, multi copying and so on. I'm having trouble avoiding double or superimposed lines of different lengths despite trying to be mindful (I'm almost positive there's a bug
at play involving the clipboard when making multiple copies of selections, but more of that later if I can confirm it)

I know the pro version has filters and stuff to find duplicate lines. It also probably has the option to use semitransparent line colors, but I want to know what can be done in the free version to catch duplicates before it's too "late". Only thing that comes to mind is to keep track of the number of lines of the base polygons in the property editor before and after multiplying them.

I'm also thinking of using the HA command after selecting a polygon. If I'm not mistaken it will not create hatches when there's overlapping lines, but I'm away from my computer at the moment

There's also an option in the Select menu called select intersecting lines or something like that. I'm not too sure what it does

Any tips?

v3.27 linux

Hi,
This is not a specific problem of the CE version.

bob93 wrote: ↑

Wed Mar 19, 2025 9:01 am

I'm having trouble avoiding double or superimposed lines of different lengths

Best to avoid these because there is no method in QCAD (CE or Pro) to detect these.
Fixing this by a tool is another matter.
There will always be the question: What to keep and what to delete?
Even then, partially overlapping entities is not really solved with keeping just one of many.
Should the tool start altering content as it sees fit? Would that give the expected result? Is 'expected' always the intended result?
What with Block content that is used in different places?

I you suspect that there are 'more' lines or entities superimposed then hold down the Alt key when selecting a nearby entity.
This will select a single nearby entity or show a list of nearby entities.

bob93 wrote: ↑

Wed Mar 19, 2025 9:01 am

(I'm almost positive there's a bug
at play involving the clipboard when making multiple copies of selections, but more of that later if I can confirm it)

What is copied to the QCAD Clipboard is the current selection and that is at your discretion.
Another way would be to duplicate (DP) the selection.
The selection focus shifts to (only) the duplicates and then move (MV for example) the newly created duplicates.

bob93 wrote: ↑

Wed Mar 19, 2025 9:01 am

It also probably has the option to use semitransparent line colors

No, a semitransparent property exist for solid Hatches and bitmaps.

bob93 wrote: ↑

Wed Mar 19, 2025 9:01 am

I'm also thinking of using the HA command after selecting a polygon. If I'm not mistaken it will not create hatches when there's overlapping lines

In a way, yes ...
The real limitation is that everything must be connected at endpoints within a tolerance and that it is a perfectly closed contour.
Retracing forth and back is then not an issue.

If you generate a polygon (Polyline) with for example 'Polyline from selection' (OC) and there are superimposed line-segments (or Arcs) ...
... It may happen that QCAD connect the 'wrong' lines and the result is open because the 'other' end is not connected to something.
With the 'right' choice the contour could have been perfectly closed.

bob93 wrote: ↑

Wed Mar 19, 2025 9:01 am

There's also an option in the Select menu called select intersecting lines or something like that.

See menu Help or the online QCAD Reference Manual
More specific: (De-)Select Intersected Entities


Regards,
CVH

CVH wrote: ↑

Wed Mar 19, 2025 10:03 am

Another way would be to duplicate (DP) the selection.
The selection focus shifts to (only) the duplicates and then move (MV for example) the newly created duplicates.

Doesn't seem to work, or I don't understand. Can you give an example please?

Polyline from selection doesn't exist in Qcad free, btw

bob93 wrote: ↑

Fri Mar 21, 2025 8:10 pm

Doesn't seem to work, or I don't understand. Can you give an example please?

Duplicate (DP) makes one duplicate of what is selected.
These duplicates are in the same location and the selection focus shifts to the duplicates.
Without altering the selection start the move/copy (MV) tool.
Indicate a source reference point and a target reference point.

Again, what is selected is at your discretion.
If that includes superimposed or partially overlapping entities then it will make copies of those too.

The OC example was to explain that QCAD may take a 'wrong' turn when deciding what is connected to what when there is a choice.
A tool to eliminate partially overlapping entities is also expected to make the right decisions.
But it get really tricky when things need to be overlapping or partially overlapping.

Draw a rectangle vertically and a square that has one parallel edge centered on the long side of the rectangle.
These polygons have partially overlapping edges.
Removing the shorter version would brake the square polygon, it only looks to be a complete square.
The same happens for the rectangle when removing the longer version.
The rectangle polygon will also be broken when we remove only the duplicate part of its edge.
There is no good answer for solving this situation.
Partially overlapping edges is intended here.
Hence, there will always be the question: What to keep and what to delete?
In some cases only the designer can answer that.

Regards,
CVH