Replace Backdrop with Bound_box

john's Avatar


10 Mar, 2023 06:47 AM

I am doing a little cleanup work on my Cartan Node Library. Unless I hear a solid objection, I am going to deprecate one current node, backdrop, and replace it with a simpler node, bound_box. These changes will occur in the next 2.3 release of the library,

Backdrop took in a shape or group of shapes and returned it surrounded by a colored backdrop rectangle. I thought this would be useful, but over the last few years I only used it once. One problem with it was that I often did not want the shape grouped within the rect, and ungrouping sometimes caused a loss of structure. Since it's easy to make a backdrop on the fly without including the shape, this node added little value and was easy to do without.

I have, however, often found myself needing to create rectangles the same size or slightly bigger or smaller than a given shape or group of shapes (without the shape inside). Sometimes I need to draw a rectangle with proportions defined by some other geometry. Other times I need to use the rect with a compound or delete node. Or, if I ever do need to make a colored backdrop, a bound_box node would get me most of the way there in a single bound.

I have included a copy of this new bound_box node in the attached demo. It takes a path or geometry, adds or subtracts a margin, and returns a rect based on the bounds of the input, colored as a transparent outline. You can then recolor it if desired and either use it as the input to another node or combine and group it with other elements. A margin of x will add x pixels around all four sides of the rect, resulting a rect with dimensions (w+2x) times (h+2x). It works nicely with my corner node for finding the outer corners of shape.

Both of these nodes are dirt simple, and are easy to make on the fly. I finally decided to include bound_box in my library, though, because I found myself reinventing that wheel again and again. And I removed backdrop because it failed the same test.

Some may ask why deprecate nodes which, though not as useful as hoped, still work. I am trying to keep the size of my library to a manageable number of nodes. Each new node adds a cognitive load and makes it harder to find the node you're looking for. So my motto is "use it or lose it."


Reply to this discussion

Internal reply

Formatting help / Preview (switch to plain text) No formatting (switch to Markdown)

Attaching KB article:


Already uploaded files

  • bound_box_screenshot.png 261 KB
  • 1.11 KB

Attached Files

You can attach files up to 10MB

If you don't have an account yet, we need to confirm you're human and not a machine trying to post spam.

Keyboard shortcuts


? Show this help
ESC Blurs the current field

Comment Form

r Focus the comment reply box
^ + ↩ Submit the comment

You can use Command ⌘ instead of Control ^ on Mac

Recent Discussions

30 Nov, 2023 05:40 AM
29 Nov, 2023 01:33 PM
29 Nov, 2023 05:30 AM
28 Nov, 2023 10:03 PM
28 Nov, 2023 12:38 AM


27 Nov, 2023 04:40 AM
26 Nov, 2023 10:02 AM
22 Nov, 2023 09:33 AM
20 Nov, 2023 08:54 PM
17 Nov, 2023 01:43 AM
15 Nov, 2023 06:58 AM