sketcher methodology

[teejay03830]

hi, i am trying to create seperate parts as extrusions from seperate sketches.

however i want those seperate sketches to be derived from one master sketch containing the geometry

in the attached file you can see me geometry in blue and the sketch for one of the parts in white, i want to add more of the white 'sketches but to be drawn directly ontop of the same original geometry. so that changing the geometry sketch, the white sketches change too.

antway the desird result is to change geometry sketch and have multiple parts update accordingly.

grateful for any help

[Dougl]

no expert here but I saw in this video( https://www.youtube.com/watch?v=H9qPMf3pxxo ) how an element of another sketch can be referenced by name in some other sketch which might get you what you're wanting to do.

And probably correct building a sketch with construction lines as your "master" and then all other sketches based on constraints of that master.

But there seems to be many ways to do things in these CAD apps so maybe there's a more elegant way someone will mention.

[chrisb]

See Sketcher External. If the master sketch is not in the same body, use a ShapeBinder.

[teejay03830]

ok great, combined with the discovery of the part design workbench (as opposed to starting in sketcher) and a better understanding of what a body is

the use of sketcher external seems to be the answer i woos looking for.

thanks

[teejay03830]

also Carbon Copy achieves the desired result
https://wiki.freecadweb.org/Sketcher_CarbonCopy

[kisolre]

But you should be careful and plan ahead because of topological naming problems that might arise.
For the CarbonCopy to properly work you need your master sketch to be fully constrained and properly defined at the beginning, before using it in other sketches. For the External geometry you should have all referenced elements be normal (not construction) geometry and they should not change order in the future - e.g. you can not delete an edge and then recreate it or change an edge from real to construction geometry. This will change the order of edges and so if the referenced edge is after that point (in order of creation) it will most probably change, braking the reference.