How to create profile for path that is not closed loop

I have a drawing of the outline of a dog (our Rodesian Ridgeback Koa) great dog.  I first used Inkscape and did a trace bitmap to outline the edges.  Then it suggested grouping the separate edges that were not and shouldn't be connected to make it one group of nodes.  I then imported it and was able to extrude it to give it some shape.
then the fun begins.  Every time I try to combine the segments (node to node) all I get is "not a closed loop"  some are and some are not and shouldn't be.  
I think I am missing some understanding of just how Freecad looks and treats some of these segments.  I like to create drawings and be able to import them into engravable or cut out objects.  I work with a lot of artists who look for this sort of capability.

Would greatly appreciate some insight as to what is going on and what I am not understanding.

Many thanks
Routerworks

Thank you. I used that however when I get to freecad it doesn't want to engrave all the edges that don't form a closed loop. Even if I separate the groups it soems it still doesn't see closed loops as closed.

I'm missing something.

Thanks again

To be honest I had no idea linuxcnc had software that would generate g code. When I started with this a few years ago I have been using Freecad to design different mechanical parts, some of which would be cut out of wood. I just continued with this. Inkscape is commonly used to generate svg files that can be used in Freecad. I also use Blender to create bas-reliefs to do what I think you are talking about. Blendercam also generates surface milling g codes that Freecad has some difficulty with.

Not to get too long winded, I simply want to be able to draw something in Inkscape, some closed loop and some curved lines that are not connected beginning to end, export it as a svg, import it into something and generate a g code.

I should probably look to the Freecad community for the answer to this. I will definitely look into what CAD CAM capabilities are available from linuxcnc.

Thanks for all you help