Making Useable Woodworking SVG From A Paper Pattern

[drlarrye]

A little background first...I have a Shaper Origin, which is sort of a handheld CNC machine that I would like to use to make some things that I only have a paper pattern for.  I asked for (and received) some help for a similar project a few days ago but that was for a CAD or drawing program image converted to a SVG.  What I am working on now was originally a JPEG.  I used Trace Bitmap on the image and each object has it's own path...actually 2 paths because they are each a circle in a circle.  Now I want to create a circle with a specific stroke and fill and snap to each of the existing circles, and delete the existing circles.  The problem is that even though there are many individual paths they are all being treated as one object.  There are no bounding boxes to snap to and though I can change their shapes individually, I can only delete them all at once, not one at a time.  (It will snap to the center hole because that is the center of the entire image.)

This particular project might be easier to make from scratch, but I have more complex ones to try later and want to learn the procedure on a simpler image.  I have attached the image if that will help.

Thanks

[drlarrye]

Found the Break Apart command.  Works now!!

[brynn]

It might not always be Break Apart that is needed.  Sometimes you will need to Ungroup.  (sometimes both)  In fact, from Trace Bitmap, I would have expected that you needed to Ungroup.

Although it's possible you are using only the Node tool, in which case you might not notice that they are grouped.  But if they are grouped, it's likely you either won't get the correct gcode, or if you use some other technique (besides gcode) it might not cut.  (The machine won't see the paths, only the group.)  So it's probably a good idea to switch to the Selection tool, to make sure there isn't a group.

Also note that there are way more snap targets than bounding boxes and centers.  In fact, I almost never use bounding boxes for snapping.  Especially if you're using a visual bounding box, it will be much more precise to snap to nodes or other targets.  Or else if you want to continue to use bounding box for snapping, switch to using geometric bounding box.

You may have noticed that when you change the width of a stroke, the size of the object changes?  That's because of the visual bounding box.  It's always aligned to the outer edge of the object (and making the stroke wider makes the whole object wider).  If you were to apply a filter to an object, that's another common way for object sizes to change.

But the geometric bounding box is aligned to the outer nodes or handles.  So changing a stroke width does not affect the size of the object.  I actually don't know why the visual bb is the default.  To my way of thinking, the geometric bb should be the default.  But anyway, that will help with precision, if precision is important to your work.

Just a few extra tips 

[drlarrye]

Now that you mention it, I'm pretty sure I "Ungrouped" also but as it didn't appear to do anything I kind of forgot about it.  I'm glad you mentioned it because next time I would've gone straight to "Break Apart" and wondered why it didn't work this time.  The centers of the bounding boxes seemed to be placed where I needed them because after I placed my circles and deleted the original everything was fine.  I appreciate the comments and suggestions because I am going to try some more complicated patterns soon and will need to know what I am doing.

What is the difference between "Break Apart" and "Ungroup"?  On the surface they sound the same.  (An explanation or a link to a proper tutorial would be great)

Thanks

[brynn]

In some cases, Ungroup and Break Apart appear to do exactly the same thing.  But not in all cases.  Since I didn't see exactly what was happening on your canvas, I can only guess.  So I'll just explain in general.  I don't know of any tutorials about this.

A group is a collection of objects.  They can be any kind of objects -- paths, shapes, other groups, clones, text, etc.  It makes all the objects in the group act like one object.  So Ungroup makes them individual objects, as before.  They go back to being clones or text or shapes or paths, or whatever the were.  Hhm....well they never stopped being those things before.  They were just in a group, so they could only act like a group - a single object.

(Note that it is possible to have a group of one.  But most of the time, it's either because of a newbie mistake, or a file conversion.  Inkscape handles some file conversions by putting everything in a group, so often there will be groups of 1.  And there are....well I guess I only know of one legitimate reason to make a group of 1, but there could be some I've never heard of.  Also, note that groups can be nested -- group of groups of groups, etc.)

Just like Ungroup is the opposite of Group, Break Apart is the opposite of Combine.  When 2 or more single paths are Combined, it creates a compound path.  So it's analogous to a group, but a compound path can only have paths in it.

In your case, I would guess you had a group of one compound path.  But that's just a guess.

[Moini]

Additionally: A compound path is a single object, that can only have a single style, consisting of subpaths that need not be connected to each other at their ends.