Remove a surface from another one from a 2d dgn file

RE: Remove a surface from another one from a 2d dgn file

Barry Lothian — Tue, 05 Apr 2022 19:39:08 GMT

No problem, happy to help.

RE: Remove a surface from another one from a 2d dgn file

DAMIEN D'ORAZIO — Tue, 05 Apr 2022 19:37:42 GMT

Brilliant, Barry, you ve just made my day. The explanation is crystal clear and the gif is just the cherry on the top.

many thanks Barry

RE: Remove a surface from another one from a 2d dgn file

Barry Lothian — Tue, 05 Apr 2022 18:31:33 GMT

There are a number of different ways to do it, using Create Region once again is likely the simplest:

Here I draw 6 lines equally spaced apart; 6 because I know it will result in 8 pieces due to the size of the circle but you need to work out how your splits need to be configured. Once I did that, I locked the lines and the group hole element. Then I activate Create Region again and enable Keep Original so that my new smaller regions will not be deleted by another new region which shares a boundary. Once I have created the individual regions, I unlock all and delete the lines and the original grouped hole element.

Other ways to do it:

Fence Move in Clip Mode (slow and awkward)
Copy the Grouped Hole into a 3D Model, extrude it, draw the lines again and use 'Cut Solid by Curves' with Split enabled. Then extract the faces of the solid and you end up with the same result as above.

RE: Remove a surface from another one from a 2d dgn file

DAMIEN D'ORAZIO — Tue, 05 Apr 2022 17:59:00 GMT

This is great I solved my first issue, tank you very much for your time, Barry you rock!!

Do you have any lead for the second part of my problem?

Thanks anyway

RE: Remove a surface from another one from a 2d dgn file

Barry Lothian — Tue, 05 Apr 2022 17:49:36 GMT

Ok using a simple example:

This is the Create Region tool in action. With the visible settings, you can see it has created a grouped hole element with the circle removed from the square. We can now chop this up into smaller pieces with further steps.

RE: Remove a surface from another one from a 2d dgn file

DAMIEN D'ORAZIO — Tue, 05 Apr 2022 17:48:02 GMT

Let s say the source shape is 120sq kilometers , it is kilometers I ve made a typo. Minus the round shape it gives you a lesser surface it doesn t matter. The main goals here are to remove the circle shape from the square shape(basically I don t know how to do it. And to create 8 shapes that are smaller than 15sq kilometers each in order to create a gml from each shapes that will be used by an app which has 15sq kilometers limit.

RE: Remove a surface from another one from a 2d dgn file

Barry Lothian — Tue, 05 Apr 2022 17:33:58 GMT

I can demonstrate the process, what isn't clear is the size of your source shapes, and how you determine that each portion will be <15sqm i.e is the 15sqm inclusive of the removed part of the outer shape, or only measured as the remainder?

RE: Remove a surface from another one from a 2d dgn file

DAMIEN D'ORAZIO — Tue, 05 Apr 2022 17:28:39 GMT

It doesn't matter as long as each of the 8 surfaces are less than 15sq meters

RE: Remove a surface from another one from a 2d dgn file

Barry Lothian — Tue, 05 Apr 2022 07:14:42 GMT

Hi Damien,

What shape are the final polygons i.e. when you intend to break the source polygon up into 8 pieces?

Rectangular slices, squares, triangles?

RE: Remove a surface from another one from a 2d dgn file

DAMIEN D'ORAZIO — Tue, 05 Apr 2022 04:59:40 GMT

Hi Barry,

Planar shapes

RE: Remove a surface from another one from a 2d dgn file

Barry Lothian — Mon, 04 Apr 2022 20:57:43 GMT

Are we talking about planar shapes, or actual surfaces like 3D topography?

Tool to be used: Create Region

If you provide a bit more info, I'll be able to give you a more definitive answer