Identification of faces

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wandererfan
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Joined: Tue Nov 06, 2012 5:42 pm

Re: Identification of faces

Post by wandererfan » Thu Jan 02, 2020 4:36 pm

AtD wrote:
Thu Jan 02, 2020 8:08 am
I used a cube and a rectangular cut to slice it, so one of the original faces is split in two, forcing FreeCAD to rename it and other faces as well.
In fact, nothing is "renamed". The original faces are thrown away, and a new set created. The sequence of the new set may or may not be a partial match to the old set.
Using the face area and bounding boxes as references, I was able to track the face names during the design process. I did this in my free time so maybe I can provide my solution here once its finished (still have some minor numbering issue).
A solution that remembers what a piece of geometry (topology?) looked like in the previous incarnation and can find the most similar piece in the current incarnation is likely the ultimate solution to the "topological naming" problem. This is how people do it - "edge16 in this feature looks the most like edge 3 in the previous feature, so it must be the same one". Perhaps something from the computer vision field.
I was a bit confused by this either, since I expected the Faces to have some property like "name" or "id" which would be updated in each step. But I found that "generating" the name from the list indeces gives the same numbering FreeCAD shows in the GUI.
see the first point.
AtD
Posts: 23
Joined: Mon Mar 18, 2019 7:14 am

Re: Identification of faces

Post by AtD » Thu Jan 02, 2020 5:25 pm

In fact, nothing is "renamed". The original faces are thrown away, and a new set created. The sequence of the new set may or may not be a partial match to the old set.
Of course, please excuse me here. I tend to say "rename" because from a human point of view, the entities stay the same while only their names change. Also I must address them with their names later, so thats all I am looking for.
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