Re-using parts of a sketch (solved)

[ConstrucThor]

Dear valuable community,

I have a question on how to re-use sketches in other sketches, without using edges linked to external geometry.
The basic idea of the final result is sketched here:

characters_on_face.PNG (209.03 KiB) Viewed 472 times

The freecad-file is also attached:

characters_on_face.FCStd

(36.12 KiB) Downloaded 10 times

There ist a square pad and there are some (goal: around 120) characters to be cut out.
Each character is sketched within its own character-master-sketch.
The characters should then placed on a plane using a master sketch. I think this would be a convenient method. Placing the characters by x-y-coordinates would be a exaustive workaround.
All sketches are then somehow combined in one pocket sketch. This sketch is then used to cut out the multiple characters.
If a master sketch for one character is modified, each occurence of that character shoud be updated automatically.

Is there any workflow known for that idea?

Methods, that I have tried out are the following:
1.) Create a carbon copy of each character. The disadvantage is, that an update of one master-character is not transfered to copys.
2.) Using "edges liked to external geometry". This works in principal, but every contour section has to be re-drawn by hand.
3.) Using Links to character-master-sketches and then mapping these links to vertecies of the master sketch was not successful, because the mapping of one link rules for all links of one object, meaning that links cannot be individually mapped to different vertices of the master-sketch.

The Idea behind the combination of the characters in one sketch is that the the computation of the pocket is much faster than creating one pocket for every character. The computation time for 120 characters is about 15 minutes on my computer (which is normally a fast one...). Creating a pocket with 120 characters at once takes only some seconds.

Currently, i use freecad 0.19 on Windows.

best regards,
ConstrucThor

[chrisb]

Methods, that I have tried out are the following:
1.) Create a carbon copy of each character. The disadvantage is, that an update of one master-character is not transfered to copys.

So you are doing serious changes, i.e. you add or remove edges? If not, then CarbonCopy should forward all changes in the master.

Next thing to try is using Part workbench where you extrude the characters and make a boolean cut.

[ConstrucThor]

Thank you for your hint.

Although I did not yet found a way to CarbonCopy objects and clones/copies/shapebinders in one sketch, I have found a (for me) convenient solution, that uses the Draft- and Part-WBs:

1.) The characters are sketched using the sketch WB
2.) For every character, there is a pad.
3.) For each character, there is one character-master-sketch with a point for every postition of one character. The character-master-sketch must not be bound to a base.
4.) A "point link array" is created in the Draft WB for every character and the corresponding character-master-sketch
5.) Each point link array is converted to a compound in the Draft WB
6.) All compounds is converted to a single compond, that now contains all characters
7.) A boolean operation is used to cut the all-character-compond out of a pad.

The solution satisfies all requirements: the characters can be changed afterwards, by changing the character's shape AND it is a performant way of doing it.

The files:

characters_on_face_perftest.FCStd

(34.77 KiB) Downloaded 9 times

characters_pocket_solution.PNG (34.31 KiB) Viewed 409 times

Best regards and happy freeCADing,
ConstrucThor