topic Re: finding empty 2D area in .NET Forum

finding empty 2D area

kazfukuoka — Sat, 15 Feb 2025 14:02:51 GMT

Hi Community,

This question is about 2D drawing (ignoring Z).
Is there any way to see if a rectangular area is empty?
Something like bool IsEmpty(x, y, w, h).

As a background, here is what I want to do: There are some entities of interest in the drawing.
I want to add information text close to each of those entities.
To find a space to draw the text, I want to find an empty space near each of such entities.

Re: finding empty 2D area

norman.yuan — Sat, 15 Feb 2025 20:14:29 GMT

Assume that you want to do it in a regular AutoCAD session with a MdiActiveDocument (that is, there is Editor available), you can simply use

Edit.SelectWindow() to see if the PromptResult returns OK or Error. OK means something inside the selecting window, Error mean nothing is selected (that is what you want to know). Make sure you zoom to the window before calling SelectWindow().

Re: finding empty 2D area

kazfukuoka — Sun, 16 Feb 2025 03:05:43 GMT

Thank you Norman, this will do for now.

Although Edit.SelectWindow() is handy, it cannot be the final solution because of the zooming requirement.
I wish to find a nicer solution for the future improvement.

Re: finding empty 2D area

kerry_w_brown — Sun, 16 Feb 2025 05:12:46 GMT

@kazfukuoka ,

How much user interaction will be allowed ?

Are you manually selecting the "entities of interest" ?

Regards,

Re: finding empty 2D area

kazfukuoka — Sun, 16 Feb 2025 05:42:11 GMT

Hi Kerry, I am wishing for a fully automatic way.
The "entities of interest" is created by my program.

In case user interaction is allowed,
I could use jig to let user select a good space.

Re: finding empty 2D area

a.kouchakzadeh — Sun, 16 Feb 2025 06:19:59 GMT

in that case you know the cordinates of your drawing. you can zoom extents then create a region with that rectangle.

since entities of interest are created by your programs, now you can get geometric extents of those entities and create another region.

subtract the entity regions from the large region and you will be able to get some thing. then you can convert that region to a polyline using Giles Geometry extension. then you can find the empty areas.

Re: finding empty 2D area

kerry_w_brown — Sun, 16 Feb 2025 07:11:26 GMT

@kazfukuoka wrote:
Hi Kerry, I am wishing for a fully automatic way.
The "entities of interest" is created by my program.

In case user interaction is allowed,
I could use jig to let user select a good space.

Yes, I was going to suggest using an MTEXT Jig to place the notation ( with a leader if needed )
This could fairly easily be built into the workflow loop

loop {

zoom to area of interest

create "entities of interest"

invoke Jig for relevant MText
}

Added: Link : perhaps something like this from Gilles

https://forums.autodesk.com/t5/net/how-to-crate-mtext-and-visible-with-the-cursor-amp-exit-when/m-p/7682076/highlight/true#M56833

Added afterthought: Even if you are able to develop a full automatic smart process you'll probably want/need to check processed object and each MText notation. . . . so there may not be much difference in total time spent . . . .except for the simpler code development 😀

Regards,

Re: finding empty 2D area

kazfukuoka — Tue, 18 Feb 2025 00:51:27 GMT

Both of you are right. I go with Edit.SelectWindow().

I worried too much considering the zooming step ugly.
But when the most important thing is to get the job done, such extra one step is not bad.
Working on AutoCAD requires lots of compromise anyway 😀

Thanks a lot