Hi guys,
sometimes I have to make small changes to drawings which have been done in AutoCAD by other (external) people in the past. These are usually present in DWG format.
When opening and editing these, often they do not appear as they should. If I open them in DWG TrueView (aútodesk software for viewing) they look as they should. I did check paper space as mentioned in some other posts.
I am currently experiencing such an example. Unfortunately I don't quite recall the artifacts from the last files, but for my current one what i can see is that dashed lines do not appear as they should, the display of underlining of text is incorrect (partially not there at all, partially slightly misplaced or only for part of the text), and it seems the order of objects has changed. I have some solid hatches, where there should be lines on top, but in QCAD (and a PDF printout from there) I only see the solid hatch. I can however select the hatches and bring them into the background, so the lines re-appear.
While this can be managed for this specific case, I would like to understand the systematic issue. In what way is QCAD interpreting this information differently than AutoCAD? Can this be counteracted with the right settings? The fact that in DWG TrueView it is displayed as it should tells me it must be a question of interpretation of the available data. Always searching for and fixing these artifacts manually is prone to error and tedious.
Unfortunately I can not share the drawing as the information is from work and hence confidential.
I will attach some screenshots trying to display the issues. Left side is always DWG TrueView while right side is QCAD. I hope this illustrates it sufficiently (i know they are not the best).
Also, is there any possibility to improve the performance of QCAD? Even though the resolution and quality of display seems worse as can be seen on the screenshots, the handling of the file is a bit laggy (moving around etc) while it is completely fluent in DWG TrueView.
I am on QCAD version 3.28.2
Thanks so much for the help!
Keep up the good work
DWGs look different than original
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Post one question per topic.
DWGs look different than original
- Attachments
-
- Misplaced underline.png (30.62 KiB) Viewed 920 times
-
- Linetype display.png (108.95 KiB) Viewed 920 times
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- Hatch position.png (42.28 KiB) Viewed 920 times
Re: DWGs look different than original
Hi,
QCAD is never intended to be an AutoCAD clone.
It supports most basic things based on the DXF standard.
DWG is a binary file format while DXF is the textual file format.
There are some specifics where a DXF converted from a DWG is not fully the same.
In the same way that we can not compare the licence fee we should not try to compare the performance.
We see these kind of posts on a regular base.
IMHO, professionals use professional software ... And pay professional fees.
If you are that sure that other platforms treat every dwg '1on1' then why all the fuzz, fixes and work-around's on their forums?
For your text entry:
Not all DXF formatting features are supported, some only partially, some in a different way (Stacked text for example).
Not all to none of application based special formatting is or can be supported.
Sometimes it doesn't add up to start with.
As far as I know in QCAD underlining starts after the '/L' switch and ends before an '/l' switch.
Please include the full source string so we can replicate the rendering. Indicate the font if that is not part of the source.
About dashed lines:
Lines or polylines? ... Polylines with custom width?
Using Screen-based Linetypes or not?
Is the linetype scale correct and which of the two applications is doing it correctly?
Sometimes it would be required that QCAD must adapt to something different or wrong for the sake of being compatible.
NOT at all, when this conflicts with the DXF standard, by preference where possible and ultimately it is a choice to make.
It should be possible to copy the dashed line and what extra details to a new file as example without harming confidentiality.
About rendering in general:
By default Anti-Aliasing is turned off. This requires extra rendering efforts.
The QCAD technology is rather different from that used by AutoCAD and associated applications like DWG TrueView.
At some point QCAD speed will indeed degrade more and more.
All depends on the vast amount of things and how all that is organized.
Sometimes it is merely over-complicated.
About the object order ... Can't help you there.
Unless you can come up with an example where a lower drawing order is displayed before a higher order.
I suspect that these objects have or had the same drawing order.
In such a case I presume that QCAD falls back on the handle, the newer, the more in front.
I have seen weird handle sequences in 3rd party files.
Eventually QCAD will re-order everything "As Is" sequentially upwards from zero on save - reload.
CADkey for example was able to display things sorted or in the forward or in the backward order.
And that also influenced selecting entities among other things.
Regards,
CVH
QCAD is never intended to be an AutoCAD clone.
It supports most basic things based on the DXF standard.
DWG is a binary file format while DXF is the textual file format.
There are some specifics where a DXF converted from a DWG is not fully the same.
In the same way that we can not compare the licence fee we should not try to compare the performance.
We see these kind of posts on a regular base.
IMHO, professionals use professional software ... And pay professional fees.
If you are that sure that other platforms treat every dwg '1on1' then why all the fuzz, fixes and work-around's on their forums?
For your text entry:
Not all DXF formatting features are supported, some only partially, some in a different way (Stacked text for example).
Not all to none of application based special formatting is or can be supported.
Sometimes it doesn't add up to start with.
As far as I know in QCAD underlining starts after the '/L' switch and ends before an '/l' switch.
Please include the full source string so we can replicate the rendering. Indicate the font if that is not part of the source.
About dashed lines:
Lines or polylines? ... Polylines with custom width?
Using Screen-based Linetypes or not?
Is the linetype scale correct and which of the two applications is doing it correctly?
Sometimes it would be required that QCAD must adapt to something different or wrong for the sake of being compatible.
NOT at all, when this conflicts with the DXF standard, by preference where possible and ultimately it is a choice to make.
It should be possible to copy the dashed line and what extra details to a new file as example without harming confidentiality.
About rendering in general:
By default Anti-Aliasing is turned off. This requires extra rendering efforts.
The QCAD technology is rather different from that used by AutoCAD and associated applications like DWG TrueView.
At some point QCAD speed will indeed degrade more and more.
All depends on the vast amount of things and how all that is organized.
Sometimes it is merely over-complicated.
About the object order ... Can't help you there.
Unless you can come up with an example where a lower drawing order is displayed before a higher order.
I suspect that these objects have or had the same drawing order.
In such a case I presume that QCAD falls back on the handle, the newer, the more in front.
I have seen weird handle sequences in 3rd party files.
Eventually QCAD will re-order everything "As Is" sequentially upwards from zero on save - reload.
CADkey for example was able to display things sorted or in the forward or in the backward order.
And that also influenced selecting entities among other things.
Regards,
CVH
Last edited by CVH on Wed Feb 28, 2024 11:22 am, edited 1 time in total.
Re: DWGs look different than original
Hi,
first and foremost thanks for taking the time for such a detailed reply and sorry for not getting back sooner.
I did not mean to offend or criticize, nor did I want to hint at QCAD not being "capable enough" in any way.
I see the difference in pricing and much appreciate having such a powerful tool available at low cost. Apologies if it came across differently.
That being said, I honestly do not understand much of what is going on behind the curtains, different file formats and inner workings of the programs. I was merely trying to point out the fact that DWGs opened in one application look different than in the other and trying to ask if there is any way around this, i.e. to have QCAD interpret the information in exactly the same way. So all I wanted to say, I would prefer if it was the same, in case it can be possible, as it would make life easier for me. You explained why this is not be possible and i partially understood
As for the linetype display, somehow I can not recreate this anymore with the same file. I have adapted the lines since and have no old version available, where this is still the case. In this specific case it was a polyine. I will have to read and understand more about the linetype scaling, display and printing as this was something that I always have to play around with to get it right in paper space after drawing in model space.
I have copied some of the text with the underline issues into a new file. What is interesting is that if when I double click the text to edit, but then just save and close without any changes, the underline changes and is displayed correctly.
For object order, do I understand it correctly that somehow QCAD is using a different handle to decide which is in front of which?
I copied the hatch fill with two lines which were originally on top but in DWGTrueView but then underneath in QCAD into the example file. However, this seems to have changed the order for good, as in this file the lines are below the hatch in both programs.
Again thank you and keep up the good work
first and foremost thanks for taking the time for such a detailed reply and sorry for not getting back sooner.
I did not mean to offend or criticize, nor did I want to hint at QCAD not being "capable enough" in any way.
I see the difference in pricing and much appreciate having such a powerful tool available at low cost. Apologies if it came across differently.
That being said, I honestly do not understand much of what is going on behind the curtains, different file formats and inner workings of the programs. I was merely trying to point out the fact that DWGs opened in one application look different than in the other and trying to ask if there is any way around this, i.e. to have QCAD interpret the information in exactly the same way. So all I wanted to say, I would prefer if it was the same, in case it can be possible, as it would make life easier for me. You explained why this is not be possible and i partially understood
As for the linetype display, somehow I can not recreate this anymore with the same file. I have adapted the lines since and have no old version available, where this is still the case. In this specific case it was a polyine. I will have to read and understand more about the linetype scaling, display and printing as this was something that I always have to play around with to get it right in paper space after drawing in model space.
I have copied some of the text with the underline issues into a new file. What is interesting is that if when I double click the text to edit, but then just save and close without any changes, the underline changes and is displayed correctly.
For object order, do I understand it correctly that somehow QCAD is using a different handle to decide which is in front of which?
I copied the hatch fill with two lines which were originally on top but in DWGTrueView but then underneath in QCAD into the example file. However, this seems to have changed the order for good, as in this file the lines are below the hatch in both programs.
Again thank you and keep up the good work
- Attachments
-
- Beispieldatei.dwg
- (17.61 KiB) Downloaded 29 times
Re: DWGs look different than original
{\LPlant Layout} => rendered as Plant Layout on Model.
And indeed rendered differently in Model compared to Text Edit.
Perhaps faulty in Model:
- All is underlined until after the first space.
- Nothing is underlined without a space.
- All is underlined without an \l switch, without curly brackets.
- Everything is perfect when using the \l switch at any point, with or without curly brackets.
I am unsure what the behavior should be without an end switch.
That may already be different within a {...} group but then I would expect the format to be in front of the group.
QCAD doesn't exploit these format groups itself.
The question remains how well these are supported and if the usage is conform DXF specs in this case.
You are probably more served with filing a Bug report on QCAD Bugtracker:
https://qcad.org/bugtracker/
You need a separate account there or create a new one.
Best is to link the report with this forum topic.
Drawing order is based on the Drawing Order property per entity.
What probably happened is that your copies are new entities.
The order of a selection of things may be arbitrary.
Meaning that new entities in arbitrary order may receive drawing orders higher than what already exists handling one at a time.
Another issue may be re-ordering from 0 and up on save-reload.
Entities with the same drawing order are diversified on something different and then I presume the handle.
It keeps the drawing order 'as is' but by definition not the values as they existed for each individual drawing entity.
For your file:
Layer 'order was changed' has handle 0x38
Text have handles 0x39-0x3b and orders 3-4-5
Lines have handles 0x3c-0x3e and orders 0-1-2
Hatch has handle 0x42 and order 6
The higher the drawing order, the more in front.
I know of applications where displaying things can be in order or in reverse order.
The layer is created before anything else.
Text are created earlier but have a higher drawing order then Lines (The original order is probably preserved in a copy)
The hatch is created last with the highest order.
We are missing 0x30, 0x3f-0x41 (Probably deleted)
I noticed that when I change the drawing order of the hatch it is a new entity with a new handle.
The handle remains the same when changing the drawing order of the lines or the text entities.
Meaning that lines and text entities are updated, hatch entities are recreated but with the intended drawing order.
I can also recreate the behavior partially when lines and the hatch had the same drawing order but the hatch was created later.
Re-ordered on reload with the hatch having the highest order.
But in no way the hatch was displayed 'under' the lines before.
QCAD can not display handles in reverse order or drawing order for that matter.
We definitely require a before and after copy if that is possible or if that is even possible with QCAD.
Regards,
CVH
And indeed rendered differently in Model compared to Text Edit.
Perhaps faulty in Model:
- All is underlined until after the first space.
- Nothing is underlined without a space.
- All is underlined without an \l switch, without curly brackets.
- Everything is perfect when using the \l switch at any point, with or without curly brackets.
I am unsure what the behavior should be without an end switch.
That may already be different within a {...} group but then I would expect the format to be in front of the group.
QCAD doesn't exploit these format groups itself.
The question remains how well these are supported and if the usage is conform DXF specs in this case.
You are probably more served with filing a Bug report on QCAD Bugtracker:
https://qcad.org/bugtracker/
You need a separate account there or create a new one.
Best is to link the report with this forum topic.
Drawing order is based on the Drawing Order property per entity.
What probably happened is that your copies are new entities.
The order of a selection of things may be arbitrary.
Meaning that new entities in arbitrary order may receive drawing orders higher than what already exists handling one at a time.
Another issue may be re-ordering from 0 and up on save-reload.
Entities with the same drawing order are diversified on something different and then I presume the handle.
It keeps the drawing order 'as is' but by definition not the values as they existed for each individual drawing entity.
For your file:
Layer 'order was changed' has handle 0x38
Text have handles 0x39-0x3b and orders 3-4-5
Lines have handles 0x3c-0x3e and orders 0-1-2
Hatch has handle 0x42 and order 6
The higher the drawing order, the more in front.
I know of applications where displaying things can be in order or in reverse order.
The layer is created before anything else.
Text are created earlier but have a higher drawing order then Lines (The original order is probably preserved in a copy)
The hatch is created last with the highest order.
We are missing 0x30, 0x3f-0x41 (Probably deleted)
I noticed that when I change the drawing order of the hatch it is a new entity with a new handle.
The handle remains the same when changing the drawing order of the lines or the text entities.
Meaning that lines and text entities are updated, hatch entities are recreated but with the intended drawing order.
I can also recreate the behavior partially when lines and the hatch had the same drawing order but the hatch was created later.
Re-ordered on reload with the hatch having the highest order.
But in no way the hatch was displayed 'under' the lines before.
QCAD can not display handles in reverse order or drawing order for that matter.
We definitely require a before and after copy if that is possible or if that is even possible with QCAD.
Regards,
CVH