What Causes QCAD To Slow Down

If you are having problems with QCAD, post here. Please report bugs through our Bug Tracker instead.

Always attach your original DXF or DWG file and mentions your QCAD version and the platform you are on.

Moderator: andrew

Forum rules

Always indicate your operating system and QCAD version.

Attach drawing files and screenshots.

Post one question per topic.

seasdes
Senior Member
Posts: 127
Joined: Tue Jan 26, 2021 2:01 pm

What Causes QCAD To Slow Down

Post by seasdes » Thu Feb 18, 2021 4:37 am

I have been happily using QCAD on a large 2 story house project over the past few days. Last night drawing lines an snapping dramatically slowed down. The file contains mostly lines, dimensions and site details. No bitmaps.

What should I be looking for before I send a file to support?

I am using the latest pro version on laptop with plenty of ram
seasdes
QCAD Pro V3.27.8
User since 2021
W10

User avatar
andrew
Site Admin
Posts: 9037
Joined: Fri Mar 30, 2007 6:07 am

Re: What Causes QCAD To Slow Down

Post by andrew » Thu Feb 18, 2021 12:34 pm

Very dense hatches can cause such problems. You might want to lower the timeout for hatch rendering under
Edit > Application Preferences > Graphics View > Appearance > Timeout for hatch rendering

For an efficient analysis, we would indeed need your file.

User avatar
andrew
Site Admin
Posts: 9037
Joined: Fri Mar 30, 2007 6:07 am

Re: What Causes QCAD To Slow Down

Post by andrew » Thu Feb 18, 2021 1:00 pm

Based on the file "210211 Booth QCAD.dwg", I cannot reproduce this here.

Can you please elaborate on "dramatically slowed down". Are we talking about a slight delay when moving the cursor (<1s)? Also is there a particular area of the drawing that is affected?

As always, please indicate what version of QCAD you're using and what operating system you are on.

seasdes
Senior Member
Posts: 127
Joined: Tue Jan 26, 2021 2:01 pm

Re: What Causes QCAD To Slow Down

Post by seasdes » Fri Feb 19, 2021 2:39 am

By dramatically I mean that it takes approx 3x longer than normally does
seasdes
QCAD Pro V3.27.8
User since 2021
W10

seasdes
Senior Member
Posts: 127
Joined: Tue Jan 26, 2021 2:01 pm

Re: What Causes QCAD To Slow Down

Post by seasdes » Mon Feb 22, 2021 6:35 am

To continue with this issue.
I think that it has something to do with snapping to items inside of blocks.
I have attached a file that shows the problem.
Snapping is instantaneous if I snap to objects that are not inside a block (Magenta colour).
Snapping slows down if I snap to objects that are inside a block (Green colour). The more copies there are of a block, the longer it takes to snap.
Zooming also slows down when focused on a block.
Also, snapping and zooming speeds up if I explode one of the blocks. The speed up occurs only on the objects that are not inside of a block.
Attachments
Slow Snapping.dwg
(51.5 KiB) Downloaded 448 times
seasdes
QCAD Pro V3.27.8
User since 2021
W10

User avatar
Husky
Moderator/Drawing Help/Testing
Posts: 4935
Joined: Wed May 11, 2011 9:25 am
Location: USA

Re: What Causes QCAD To Slow Down

Post by Husky » Mon Feb 22, 2021 7:46 am

Hmmm, I can't reproduce that on my computer. The example drawing "Slow Snapping.dwg" is fast like hell ...

Is there an explicit tool / tool combination / tool order etc. what I have to use to trigger the slow response on this drawing?
Work smart, not hard: QCad Pro
Win10/64, QcadPro, QcadCam version: Current.
If a thread is considered as "solved" please change the title of the first post to "[solved] Title..."

seasdes
Senior Member
Posts: 127
Joined: Tue Jan 26, 2021 2:01 pm

Re: What Causes QCAD To Slow Down

Post by seasdes » Mon Feb 22, 2021 7:59 am

Husky wrote:
Mon Feb 22, 2021 7:46 am
Hmmm, I can't reproduce that on my computer. The example drawing "Slow Snapping.dwg" is fast like hell ...

Is there an explicit tool / tool combination / tool order etc. what I have to use to trigger the slow response on this drawing?
Thanks Husky
Zoom in close to the blocks, pause a while and zoom in a bit closer. It should now be harder to zoom. Also by snapping - I was trying to draw a line from any position to one of the line intersections in one of the blocks. Sometimes it is fast but commonly it is not. Especially when there are many copies of a block that has a lot of lines.
seasdes
QCAD Pro V3.27.8
User since 2021
W10

User avatar
Husky
Moderator/Drawing Help/Testing
Posts: 4935
Joined: Wed May 11, 2011 9:25 am
Location: USA

Re: What Causes QCAD To Slow Down

Post by Husky » Mon Feb 22, 2021 8:49 am

Thanks seasdes - I can now reproduce the issue.

It looks to me that the blocks are inserted with an x scale of minus 1. That leads to a delay / fail of the snap function. Same block inserted with a positive scale behave absolutely normal.

@Andrew, can you take it from here? Thanks.
Work smart, not hard: QCad Pro
Win10/64, QcadPro, QcadCam version: Current.
If a thread is considered as "solved" please change the title of the first post to "[solved] Title..."

seasdes
Senior Member
Posts: 127
Joined: Tue Jan 26, 2021 2:01 pm

Re: What Causes QCAD To Slow Down

Post by seasdes » Mon Feb 22, 2021 8:59 am

Thanks Husky
That fixed it.
seasdes
QCAD Pro V3.27.8
User since 2021
W10

Giuliano69
Active Member
Posts: 36
Joined: Mon Nov 23, 2020 4:37 pm

Re: What Causes QCAD To Slow Down

Post by Giuliano69 » Sat Aug 14, 2021 11:23 pm

Hi all
I’m STILL facing this same problem with Qcad 3.26.4.0… even after setting the hatch timeout to 125

What I discovered:
-If I start zooming with the mouse over a hatch, the zoom get very slow
-If I start zooming with the mouse outside the drawing, it is very fast
-If I set the hatch to solid, no evident speed improvement appears in the zooming
-If I disable the layer with the hatch (17) the zoom is fast wherever I start zooming


As far as the problem shows now, the problem seems probably to reside in one of the following :
-the Qt/external library used to zoom
-the Qcad logic design of in the “simple” code

PS
Using

Versione:
3.26.4.0 (3.26.4)
Internet:
QCAD.org
Data Compilazione:
Jun 4 2021
Revisione:
0bb4334
Versione Qt:
5.14.2
Architettura:
x86_64
Compilatore:
gcc 5.4.0
Attachments
impianto elettrico piano terra.dwg
(383.15 KiB) Downloaded 392 times

User avatar
Husky
Moderator/Drawing Help/Testing
Posts: 4935
Joined: Wed May 11, 2011 9:25 am
Location: USA

Re: What Causes QCAD To Slow Down

Post by Husky » Sun Aug 15, 2021 2:05 am

Hi,
Giuliano69 wrote:
Sat Aug 14, 2021 11:23 pm
What I discovered:
-If I start zooming with the mouse over a hatch, the zoom get very slow
-If I start zooming with the mouse outside the drawing, it is very fast
-If I set the hatch to solid, no evident speed improvement appears in the zooming
-If I disable the layer with the hatch (17) the zoom is fast wherever I start zooming
I don't have a solution for you yet but something what I discovered makes me wondering ...

There is only one block with a hatch. If I delete that block it looks to me that we then deal with normal zoom speed in all areas regardless the mouse pointer position.
For a test - please delete(!) block A$C25522 and test it by yourself. Note: Don't save this test with the same drawing name!!!
Work smart, not hard: QCad Pro
Win10/64, QcadPro, QcadCam version: Current.
If a thread is considered as "solved" please change the title of the first post to "[solved] Title..."

CVH
Premier Member
Posts: 3416
Joined: Wed Sep 27, 2017 4:17 pm

Re: What Causes QCAD To Slow Down

Post by CVH » Mon Aug 16, 2021 6:27 am

Hi,
This seems to be a highlighting issue, something already discussed somewhere on the forum.

With your pointer inside a hatched area, QCAD will highlight the hatch as it is the nearest entity.
... Or the block including that hatch ...
And in the case: <impianto elettrico piano terra.dwg> everything inside the building is also
inside the bounding box around the block on layer '18_Retini pavimentazioni'.

Highlighting is repeated at every zoom state and the re-rendering requires some extra time.
It slows more with:
  • Dense hatching. (Many individual line segments to render)
    Multiple, nested or complex boundaries.
    Odd scaling, like -1 to mirror, or a scale in Z.
    Complex hatch patterns. (e.g. GRAVEL)
    Far hatch origin offsets or wide spans. (All hatch origins are @(0,0) or at least 50m away)
One can simply lock the layers with hatches ... e.g. Lock layer 17 and 18 of <impianto elettrico piano terra.dwg>.

Once locked, all those hatch segments don't need to be highlighted over and over again :wink:
And then it seems a good idea to isolate any hatch entity on a dedicated hatching layer.

Regards,
CVH

CVH
Premier Member
Posts: 3416
Joined: Wed Sep 27, 2017 4:17 pm

Re: What Causes QCAD To Slow Down

Post by CVH » Mon Aug 16, 2021 8:49 am

Giuliano69 wrote:
Sat Aug 14, 2021 11:23 pm
What I discovered:
-...
-If I set the hatch to solid, no evident speed improvement appears in the zooming
High speed zoom rendering is reacquired with making the 'HONEY' hatch in block 'A$C25522' solid.

When pointing inside the walls ... inside the bounding box around 'A$C25522' :
- There will not be any individual hatching segment near the pointer as there are no hatching segments at all.
- QCAD doesn't need to verify that you are pointing at block 'A$C25522' for each such hatching segment.

Exploiting this knowledge ...
High speed zoom rendering is also reacquired when hatching block 'A$C25522' in 12 parts using 'HONEY'.

Regards,
CVH

User avatar
Husky
Moderator/Drawing Help/Testing
Posts: 4935
Joined: Wed May 11, 2011 9:25 am
Location: USA

Re: What Causes QCAD To Slow Down

Post by Husky » Mon Aug 16, 2021 9:51 am

@ Giuliano69,
Husky wrote:
Sun Aug 15, 2021 2:05 am
For a test - please delete(!) block A$C25522 and test it by yourself.
Thinking again about this: The issue is definitive based in the hatch used in block A$C25522. Move that hatch from the block to model_space and you are back to normal zoom speed.
Work smart, not hard: QCad Pro
Win10/64, QcadPro, QcadCam version: Current.
If a thread is considered as "solved" please change the title of the first post to "[solved] Title..."

Giuliano69
Active Member
Posts: 36
Joined: Mon Nov 23, 2020 4:37 pm

Re: What Causes QCAD To Slow Down

Post by Giuliano69 » Mon Aug 16, 2021 4:37 pm

Thanks for your help

So far, we have learnt two type of "patches" to this bug with this hatches (I believe that we must call it bug...)
-make the block or the layer invisible. This prevent the redrawing and bypass the problem
-lock the layer where this hatch is present. this will speed up things like normal.

Anyway, when at first your receive a dwg from other company, open it and and start working on it, you DO NOT know which hatch will cause a bug in QCAD.
And you will loose time finding the "bad guy" and fix it in some way...
Please consider also that that hatch has caused no such problem on the other program that created the drawing ...

I believe that this must be consider a bug of the program (hatch engine ? snap engine ? redraw engine ?...)
Hope that the runtime debugger will help the developers find where the program hangs, and fix the routine.

BR
Giuliano

Post Reply

Return to “QCAD Troubleshooting and Problems”