XDATA, what it is for and how it works (Please)!!

[duke]

Hello friends !!
I was wondering about XDATA,
What is it for and how does it work within AUTO-LISP
Because I don't know exactly if it works for what I'm thinking.
Maybe you can create objects, for example:
CIRCLES and internally assign each circle an internal data to each one, so that each and every one of the circles has a unique and unrepeatable and totally identifiable "NAME"
Example:
To join all the circles with a polyline, in a specific order, say from the circle called internally with a number 1 (ONE), to the circle number 5 (FIVE).
Or XDATA is not used like that
I put that as an example, but if it is used for other things, could you write me a small example code to understand how XDATA works, please
Something very simple and small, you can
And in advance, thank you very much ‼‼

[Steven P]

XData is essentially an additional bit of information added to the entity definition, it doesn't change how the entity is shown on the screen. What you want to do can be done, and this link is a good description

https://www.afralisp.net/autolisp/tutorials/extended-entity-data-part-1.php

[duke]

8 hours ago, Steven P said:

XData is essentially an additional bit of information added to the entity definition, it doesn't change how the entity is shown on the screen. What you want to do can be done, and this link is a good description

https://www.afralisp.net/autolisp/tutorials/extended-entity-data-part-1.php

Great !!! i am going to read 
Thanks bro ‼‼‼

[BIGAL]

"Joining circles via creation order", using ssget can most times do this, try it, but as was posted somewhere else doing a sort on the "Handle ID" of the objects is creation order. I seem to remember must change to a number not hex.

 

Quick and dirty

(defun wow ( / ss x)
(setq ss (ssget '((0 . "CIRCLE"))))
(command "pline")
(repeat (setq x (sslength ss))
(command (cdr (assoc 10 (entget (ssname ss (setq x (1- x)))))))
)
(command "")
)
(wow)

 

Edited May 5 by BIGAL

[duke]

1 hour ago, BIGAL said:

"Joining circles via creation order", using ssget can most times do this, try it, but as was posted somewhere else doing a sort on the "Handle ID" of the objects is creation order. I seem to remember must change to a number not hex.

 

Quick and dirty

(defun wow ( / ss x)
(setq ss (ssget '((0 . "CIRCLE"))))
(command "pline")
(repeat (setq x (sslength ss))
(command (cdr (assoc 10 (entget (ssname ss (setq x (1- x)))))))
)
(command "")
)
(wow)

 

ty BIGAL
beauty example for creating a pline ‼‼‼‼‼

Edited May 5 by duke

[Jonathan Handojo]

There aren't really many applications in which you would use xdata. I can only imagine needing one when you create your own applications like you would with a dictionary, in which you would like the objects to behave and "react" differently in respond to several commands. Again, what do I know... 

 

Here is one example of one of my programs in which xdata is used. (I hardly ever use this because I hardly see its use, but I just created it as practice for myself. Hence, I stopped enhancing it.)

 

Edit: Apologies for the complex example, I didn't read the OP that it was intended to be simple...

ObjectPropertySync.lsp

Edited May 6 by Jonathan Handojo

[BIGAL]

A good tutorial and description about using XDATA.

 

https://www.afralisp.net/autolisp/tutorials/extended-entity-data-part-1.php

[АлексЮстасу]

XData are for additional non-graphical descriptive information (< 16K) that can be attached to objects.

This information can be divided into two parts - for two different main tasks:
1. For programming purposes.

As in your example with the numbers of circles defining the order in which they are connected. Or in Jonathan Handojo's ObjectPropertySync.lsp.
Etc.

AutoCAD itself uses XData for primitive's  additional data - in Dimensions, Hatches, Viewports, and so on.
2. For users - to turn their graphical models into object models.

In XData, you can define the names (or codes) of the real world entities (features) represented by your graphical primitives. For example, your circles can be defined as ‘fire hydrant’ or ‘storm well’, etc.
And in XData, you can define characteristics (attributes, properties) of reality objects (features). For example, depth, material, belonging, purpose, etc.
After that, it becomes possible to analyse the drawing as a model of reality and transfer such a model to information systems.

To work with XData, we made a set of users tools - XDTOOLS.

[АлексЮстасу]

On 5/6/2024 at 2:53 AM, Jonathan Handojo said:

Here is one example of one of my programs in which xdata is used.

I haven't understood anything yet, but the idea of linking object properties seems interesting in principle.
Can you give me a very simple example of such a link?

[Jonathan Handojo]

 

7 hours ago, АлексЮстасу said:

I haven't understood anything yet, but the idea of linking object properties seems interesting in principle.
Can you give me a very simple example of such a link?

This isn't really the most user-friendly command or approach... like I mentioned before, this was only used for my practice because I hardly see its practical use. But this is more or less how it works. If you're keen to use it, I can look to make some adjustments and improvements to make it more user-friendly.

 

For more proficient AutoLISP users, there are already sub-functions which can be called to initialise OS-ADD, OS-REM between any two objects and refreshing with OSYNC, allowing them to create their own custom commands and add them as they see fit. 

Edited September 1 by Jonathan Handojo

[АлексЮстасу]

1 hour ago, Jonathan Handojo said:

But this is more or less how it works.

The video made it clearer. Thank you!
Need to think about what it might be useful for. Or similar to this...

 

I've been interested in the topic of object linking in AutoCAD for a long time.

We've done two experimental projects using XData for linkage information:
XDLabel - to link inscriptions (Texts, MTexts, Leaders, MLeaders) to objects for which the inscriptions are needed,
XDPoint - for linking point objects (Blocks, Circles, Lines, 3dSolids, Tables and Points) to the objects for which they are created.

Can create inscriptions and point objects with the desired properties at the base objects.
Can link existing inscriptions and point objects to the objects they belong to.
Can restore the position, properties, and content of inscriptions and point objects relative to the underlying objects, or update the links.

 

I am not at all sure that we have found the optimal solution. And we are doing it as amateurs, being completely inexperienced programmers. I'm not a programmer at all.
But in principle, it works well enough.

 

These projects are largely finishe, and I am now thinking how the theme of links could be continued. But with a practical use!

Edited September 2 by АлексЮстасу

[Jonathan Handojo]

2 hours ago, АлексЮстасу said:

The video made it clearer. Thank you!
Need to think about what it might be useful for. Or similar to this...

 

I've been interested in the topic of object linking in AutoCAD for a long time.

We've done two experimental projects using XData for linkage information:
XDLabel - to link inscriptions (Texts, MTexts, Leaders, MLeaders) to objects for which the inscriptions are needed,
XDPoint - for linking point objects (Blocks, Circles, Lines, 3dSolids, Tables and Points) to the objects for which they are created.

Can create inscriptions and point objects with the desired properties at the base objects.
Can link existing inscriptions and point objects to the objects they belong to.
Can restore the position, properties, and content of inscriptions and point objects relative to the underlying objects, or update the links.

 

I am not at all sure that we have found the optimal solution. And we are doing it as amateurs, being completely inexperienced programmers. I'm not a programmer at all.
But in principle, it works well enough.

 

These projects are largely finishe, and I am now thinking how the theme of links could be continued. But with a practical use!

 

That's good on you. I normally can't think of any applications in which I would rely on xdata. Probably if you are literally trying to make an entirely new application, then you'd go about using it. In my case here, it's only between literally ANY two object properties which the AutoCAD FIELD can extract from any object... be it an insertion point, layer, text style, etc. so the ideas are boundless. What's more, the properties can be "chained" from one object that was previously linked, to another.

 

My program enhances a little further, which would allow extracting and modifying:

 

• The X, Y and Z values of a 3d-point individually
• A table cell
• Block Attributes

Edited September 2 by Jonathan Handojo

[Tsuky]

A concrete example of the use of XDATA
For example, set up these entities by copying and pasting the following lines into a new command line drawing:

(entmake
'(
(0 . "LINE")
(100 . "AcDbEntity")
(67 . 0)
(410 . "Model")
(8 . "0")
(100 . "AcDbLine")
(10 4.1142e+06 1.95551e+06 0.0)
(11 4.11734e+06 1.9574e+06 0.0)
(210 0.0 0.0 1.0)
)
)
(entmake
'(
(0 . "CIRCLE")
(100 . "AcDbEntity")
(67 . 0)
(410 . "Model")
(8 . "0")
(100 . "AcDbCircle")
(10 4.11683e+06 1.95826e+06 0.0)
(40 . 800.0)
(210 0.0 0.0 1.0)
)
)

Make an extended zoom and apply the following routine (it's in French, I didn't translate it for the example)

Clothoide

You get a simple polyline, but with this you will get the technical information that was used to build it.

IdClo

 

clothoide.lsp idclo.lsp