Hello,

I am trying to draw a schematic diagram with Inkscape, and it is very important to me that all the parts of my schematic stay "on grid".

This is fine when editing individual components (each component is a group) because I can select the group and snap cusp nodes inside the group to the grid - easy.

But sometimes, when I select large numbers of objects, like if I want to move the entire diagram around on the page, I lose this ability to snap to cusp nodes. The only snap I get is "snap convex hull corner to grid intersection", which is off-grid with relation to the objects I am trying to snap. This happens regardless of the snapping options I have selected. At this point, once the diagram is off grid, I can no longer get it back onto the grid again without moving individual objects or smaller selection sets of objects.

Why is it, when operating on small numbers of groups, I can snap to nodes within the selection set, but with large numbers of objects, I lose this ability and can only snap to the convex hull corner?

I have attached an example. If you select the entire drawing and try to move it, it can't be snapped such that all components and lines are on the 0.1" grid.

mightyohm wrote:Why is it, when operating on small numbers of groups, I can snap to nodes within the selection set, but with large numbers of objects, I lose this ability and can only snap to the convex hull corner?

Because with default snap mode there would just be too many snapping possibilities to the grid.

You can change the snapping preferences to only snap the node closest to the pointer i.e. the node closest to where you grabbed the selection to drag it:

File > Inkscape Preferences > Snapping:

[x] Only snap the node closest to the pointer

[Edit]
BTW - a google search for "snap convex hull corner to grid intersection" leads you directly to the Inkscape manual page about snapping:
«A few other options can be found under the Snapping section of the Inkscape Preferences dialog:

• (…)
• Only snap the node closest to pointer: If this option is enabled, only one node is used as a snapping point on a target. This node will be highlighted as an object is dragged. Useful if an object has many snapping points. Note: if an object has too many nodes, and this option is disabled, a “convex hull”[9] is used for snapping.»

[/Edit]

Thank you so much! With this option turned on, I can move my entire schematic and still snap individual nodes to the grid. Awesome!

Interesting that Inkscape seems to show this behavior for small collections of objects regardless of the preference setting. It will tend to use the snap closest to the mouse pointer. I didn't realize I had to explicitly set a preference option to enable this for larger collections of objects.

Thanks again, this will save me hours of work moving individual objects!