LibreCAD for Building Survey projects

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LibreCAD for Building Survey projects

Tim Payne
Hi All,
I have a Terrestrial Laser Scanner, with which I have acquired data on several likely projects.
I have upgraded to Version: 2.2.0-rc3-24-g4602ec6a
Compiler: GNU GCC 7.3.0
Compiled on: Mar  5 2022
Qt Version: 5.12.4
Boost Version: 1.65.1
System: Windows 10 (10.0)
from LibreCAD v2.103

As a Surveyor I have no requirement for Architectural (design / new-build software), just an app that I can use to trace over a generated "object".
I have registered a number of point clouds together, of a buiding of interest, extracted a very thin horizontal slice from the registered point cloud (this gives a floor plan), then saved as a .dxf file, however, the plan oulines have to be "traced" over, in an app such as LibreCAD, to generate a workable, dimensioned deliverable.

However, the file dxf point cloud is large (only 40MB) for LC and makes it difficult to manipulate or operate drawing tools, so I thought that if I acquired a top down image of this point cloud, then I could import that and trace out the floor plan over this image.

However, if I insert a top-down BMP image to a new layer in LC, the image displays, if Draft is NOT selected. If I select Draft, then the image disappears.

The concept was proved by Gary Fox in two You Tube tutorials "Tracing a picture with LibreCAD Pts 1 & 2", but he was using an old (?) version of LibreCAD and he used a JPG to trace over. (I've tried PNG, JPG & BMP all with the same result...).

Any advice greatly appreciated.

TP
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Re: LibreCAD for Building Survey projects

perepujal
Hi,
If the slice could be exported to a .csv file and the points are in order, then the plugin "Read ascii points" could help you to trace lines between points, check the "connect points" box

About the image disappearing when Draft is selected, yes, this is intended to allow redrawing the screen quickly.

And about the image covering the points/lines, if this happens, clicking on the image, it brings it to front/bottom, but I could not find the pattern behavior when there are overlapping images.

HTH
Pere
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Re: LibreCAD for Building Survey projects

Tim Payne
Hi Pere,

Thanks a lot for your very quick response - I had not considered an ascii point file, so will have a go at that later.

In the mean time the concept of "Raise over / lower after entity" is gradually becoming more clear and have managed to create some polylines over internal walls, over the BMP image.

Still having problems with selecting individual lines for deletion or editing, but am sure that there are you-tube videos dealing with that.

Your suggestion much appreciated and will report back on ascii progress, as and when.

Thanks and regards,

Tim.
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Re: LibreCAD for Building Survey projects

dellus
The problem with selecting lines above an image is that always the image gets selected. Furthermore the image is pulled to the foreground (it is highlighted) as long as it is selected, thus covering the lines. It even doesn't help to lock the layer with the image, you can't select anything at all within the image area then.
A workaround suitable in some situations is to select lines by pulling up a rectangle with the mouse, from left to right around the lines, or from right to left just partially touching them. The latter can simulate selecting like with a single mouseclick, but you can't deselect this way if you unintentionally have selected a wrong part.
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Re: LibreCAD for Building Survey projects

Tim Payne
Hi Dellus,

Thanks very much for your input - unfortunately I have to go back to "school" and learn some basics, like slsecting lines / objects and closing / editing polylines, before I can get excited about tracing lines over image walls - very frustrating, but I guess that there is some guidance in the plethora of You-Tube vids available on line.

Hope to be able to report some progress in the near future or will have to accept that there is not really an answer to this, other than the ACAD / Revit route, which is unacceptable (to me) due to crippling subscriptions...

Thanks & regards,

Tim.
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Re: LibreCAD for Building Survey projects

perepujal
In reply to this post by dellus
Just hold the Shift key to unselect items with rectangle, works both right to left and left to right
HTH
Pere
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Re: LibreCAD for Building Survey projects

dellus
Ah, thanks Pere, a good tip.
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Re: LibreCAD for Building Survey projects

Tim Payne
In reply to this post by perepujal
Pere,

Thanks for the tip, will employ as and when (if I get to that stage).

I tried the ascii format, which does work (more clear if not joined up) however, the number of ascii points is about the same as the dxf "bits", that are saved as dxf in Cloud Compare, so not a great improvement (with regards to time delays in using tools) for actually working / tracing.

Am still experimenting with the bmp image which is easy to work on, but with inconsistent tool actions, possibly due to working over the image (at bottom of selection and with draft off).

I had drawn a polyline rectangle about the property, but due to large scale, the start and end points are not joined. I can't find a method of selecting these two points and joining them together...

I feel that polylines have to be used to give a true representation of the (as-Found) structure, rather than inputting mathematical constructs like rectangles (ideal for design), where corners between walls may not be right angled.

Anyway, I'll keep on reviewing some of the handy You-Tube tutorial videos.

Many thanks for your input - greatly appreciated.

Tim.  
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Re: LibreCAD for Building Survey projects

Tim Payne
Version: 2.2.0-rc3-24-g4602ec6a
Compiler: GNU GCC 7.3.0
Compiled on: Mar  5 2022
Qt Version: 5.12.4
Boost Version: 1.65.1
System: Windows 10 (10.0)


I have made some progress: building and room outlines.

I thought that door frames would be worthy of a block, however, on completing the block and returning to the Layer List, I couldn't return to the original drawing location. I tried autozoom, zoomed out to a stupid scale, back in again, still nothing.

I closed the drawing, went back to a previous effort and wrote down the co-ords of a buiding corner, closed that drawing and reopened the drawing with blocks and set those co-ords to the Relative Zero position, which brought the corner of the drawing back into view.

I went to import the door block, which... I couldn't - it didn't sem to get past the reference point request, so abandoned that, checked the block, seemed OK, but on trying to return to the main drawing, it had vanished - this time the relative zero was in the correct location, so don't know where that data has gone.

Needless to say the Layer list has the same population, just not displayed anywhere...

Any hints gratefully received.

Tim.
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Re: LibreCAD for Building Survey projects

Jaycad
LibreCad repeats a command until you terminate it so when you choose File-->Import, then pick your block from the browser, then pick your placement point, the program waits for you to place another block instance or terminate the command.  It may look like nothing is happening.

Regarding your block, I had a block not appearing at the placement point in my drawing but when I edited my block (a bath tub) and shifted one corner to the zero origin, it worked fine on import.  Hope that helps.
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Re: LibreCAD for Building Survey projects

Tim Payne
Hi Jaycad,

Thanks for your response.

Have muddled through to a basic 2D floor plan.

I cannot get the dimension tool to work - not sure if its a layer issue or something else - have watched at least three video tutorials, all of which seem to make the selection of points and subsequent dimension line positioning appear very simple.

At the "top" end of my drawing, I would like to dimension the width of the apartment, however, after selecting the base line points and positioning the cursor above this line, nothing happens - the dimension line will not go above the proposed dimension edge... Have just tried positioning below the line (inside the Plan) and it will position there, but this is no good for a presentation / print out.

There doesn't seem to be anything else that I can adjust in Drawing Preferences.


Best regards,

Tim.
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Re: LibreCAD for Building Survey projects

Jaycad
Hi Tim,

I had a similar problem which was resolved by turning off snaps.  I used end snaps to place the dimension end points then found that I could not position the dimension line where I wanted it.  After turning off snaps I was able to position it.

LibreCad snaps are very "magnetic"!

Incidentally, I draw and model buildings from pointclouds so I well know that they cost an arm and a leg, especially when you add plugins to improve point cloud management.  I know that cheaper programs like ProgeCad and Gstars can import point clouds that cannot manage them very much beyond that - slicing, for example.

I have a friend who uses GStars and uses Recap or other software to cut slices and sections from the cloud, which are then imported into Gstars.
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Re: LibreCAD for Building Survey projects

dellus
I recommend to have Free Snap on all the time, together with other snaps you want to use.
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Re: LibreCAD for Building Survey projects

Jaycad
Thanks dellus, I forgot to mention free snap
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Re: LibreCAD for Building Survey projects

Tim Payne
Pere, Delu & Jaycad,

Thanks to your input and advice, I have now advanced to a 2D dimensioned drawing of my apartment, derived from Terrestrial Laser Scanner measurements (after a short break for work).

I also followed a demo to make a drawing Template for A2 size subjects, as the floor plan scaled to 1:50 should fit within this template.

I also placed this Template within the LC Library/Templates folder (after removing the original file) - so on opening LC, the screen is set to this 1:50 scale Template for A2 paper.

So, I thought that by opening the Floor Plan file, I would be able to rescale it and include it in the Template, however, when the Floor Plan file starts up, the Template file disappears and when I have the Floor Plan file loaded, on selection of Print Preview it opens on a blank sheet, which is overlapped by the Floor Plan, until rescaled to 1:50.

Is it possible to get that template included in Print Preview, so that the content can be positioned as necessary?

For dimensioning in the 1:1 drawing, I made the General Scale: 50, so that values were legible and dimension arrowheads were visible.

I have tried rescaling the Floor Plan file to 1:50, then dropping it onto the Template, but all the life size 1:1 dimensions revert to the sizes of the actual drawing, so where the floor plan is 14587 mm along one side, the resulting Template display is 292 mm.

Seems quite complex, but am sure that there is a way to get the two merged together, correctly?

Kind regards,

Tim Payne
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Re: LibreCAD for Building Survey projects

Tim Payne
My apologies to Dellus for misspelling your handle
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Re: LibreCAD for Building Survey projects

dellus
In reply to this post by Tim Payne
Leave the floorplan at 1:1. Scale up the A2 template x50. Then import the floorplan into the template or vice versa. You also may scale up a 1:1 template after importing. That's the way to go.
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Re: LibreCAD for Building Survey projects

Tim Payne
Hi Dellus,

Thanks for your rapid response - haven't tried it yet, but do you end up with a sheet of paper 29 700 mm x 21 000 mm?

Do you change the scale back again at print preview?

Thanks & regards,

Tim.
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Re: LibreCAD for Building Survey projects

dellus
In Print Preview you have to set 1:50 then.
Here is a very basic sample how it has to look:
floorplan_sample.dxf
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Re: LibreCAD for Building Survey projects

Tim Payne
Hi Dellus,

Thanks for your perseverence and I will try this out in the near future.

Unfortunately, work has intervened, so I don't have time at the moment to get back into my project, but when I've established myself in another "office" I will get back to trying out your hints & tips and advise accordingly.

BR

Tim.
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