Sketch using external geometry to do a pocket

[ryansturmer]

I have created a sketch by bringing in lines and arcs that reference an external geometry. I am trying to use it to pocket a face:

Screen Shot 2017-04-17 at 8.44.25 AM.png (15.84 KiB) Viewed 1293 times

The red lines and arcs are the ones brought in by referencing the external geometry, and the green line is one I added by connecting the two endpoints from the external geometries. (I understand that green means fully constrained?)

This skech seems OK, but when I try to reference it to do my pocket, it doesn't look right - only the green line in my sketch shows up in the preview of the pocketing operation. If I attempt to accept the pocket operation anyway - it complains: "Failed to create face from Sketch" - Any idea what I'm doing wrong here?

Screen Shot 2017-04-17 at 8.52.58 AM.png (60.25 KiB) Viewed 1293 times

OS: Mac OS X
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Branch: tag: 0.16.6706
Hash: f86a4e411ff7848dea98d7242f43b7774bee8fa0
Python version: 2.7.11
Qt version: 4.8.7
Coin version: 3.1.3
OCC version: 6.8.0.oce-0.17

[renatorivo]

Hi,
see https://www.freecadweb.org/wiki/Sketcher_External

When a sketch is mapped to a face of a solid, the Sketcher External Geometry tool can be used to link to an edge or vertex of that solid. It works by inserting a linked construction geometry into the sketch. The default colour of externally linked edges, is magenta. As with standard non-linked construction geometry (blue), the externally linked geometry is only visible when the sketch is in edit mode and is not directly used in the subsequent result, from use of the sketch in another tool. Both types of construction geometry are used as a reference for constraints, within the sketch.

Renato

[Willem]

Hi, you say in your sketch is only a line. You can not pocket a line. The sketch must contain a closed shape, so e.g. a rectangle can be pocketed

[chrisb]

You would be better off if you imported only the endpoints of the external geometry where possible, then you can see the lines of your current sketch which should connect the points. The external lines are lying on top of the sketch's lines. It may be necessary to import the arc segments as they are in order to get the radius.

Recently developer Abdullah has made an extension to change that behaviour.

[UR_]

No advice, just found:
https://forum.freecadweb.org/viewtopic.php?f=3&t=15987