Parametric slot size changes

Hi, can anyone recommend an easy way to resize 3d models so that as they scale up or down in size, i can also change thickness of slots for different material thicknesses?

the search term you want is “parametric” or maybe “parameterizing”
I don’t know which 3d program you use, but there are some good community tutorials here:
3d Software Matrix


You didn’t specify what program you’re using. The answer will change between programs and there are some apps for which parameterizing anything is nigh impossible.

Assuming Fusion 360 for the moment, though any worthy CAD program can do the same, the key is two fold;

  1. Capture the material’s thickness as a parameter. Use that value for all of your extrusion operations (operations that turn your 2D sketch into a 3D object). And use it for the width of any slots.

  2. Very carefully apply geometry constraints such that changing material thickness preserves the overall design and layout of whatever your building.

Sounds easy. There are sharp edges that very between programs. For example, in Fusion 360, there are certain 2D operations that cannot be dimensioned or parameterized. A specific example; the # of sides in the 2D polygon cannot be parameterized (fortunately, it is really easy to use the circular repeating pattern operation to create a fully parameterized polygon!).

This is the best tutorial video I’ve found for F360 and it really nails how to parameterize a model! While F360 specific, the general concept would apply to any CAD package.


You can semi-parameterize your slots in inkscape via clever use of clones.


Can you elaborate on this please?

Make a slot the size you want. Then create a clone (or many clones) and paste those into your design where you need them.

When you want to resize to a new thickness of material, simply change the first slot object. All of its clones will update to the new change automatically.


(Apologies to beginners, this won’t make a ton of sense unless you are pretty decent with Inkscape already)

What @jamesdhatch said, more or less. There are a couple gotchas here, if your design is really precise and need to be properly aligned for symmetry’s sake (which it probably is if you’re worried about this), you need to be careful when resizing your slot master object.

Basically say your slot is currently 1/4", but you want it to be 1/8", it’s not enough to just halve its width, because that will scale using the left edge as an absolute position. This will mean that the center of the master will slide slightly left (1/16" left, to be exact), which will in turn move all your clones “left” (left is relative with clones, depending on how you’ve rotated them post-cloning).

To counter this, when changing the size of your master object, manipulate the nodes: Move the left side nodes to the right by 1/16" and the right side nodes shift left 1/16". That way the center of the slot object is right where it started, and your clones will be just where you wanted them.

Often my slot objects are “U” shaped. I don’t make them whole rectangles, which allows me to see which way the clones are oriented. This is nice if you need to also change depth of the slots, because now you can just extend or retract the “bottom” of the U, and you know that it’ll extend/retract into your main pieces.

The second gotcha to remember in Inkscape:
Copy/pasting of clone objects into a new document will cause you great consternation. They paste very unreliably, as they don’t have a master object to refer to.

If you want to take your resized objects and save them out to a new document for later use, I recommend the laborious but proven method:

  • copy and paste all your cloned objects into the same document, so you now have two copies of everything.
  • Select the entire duplicate set of cloned objects

  • Unlink the clones.

  • Cut the now unlinked objects

  • Paste into your new document and save away.

It’s a bit overkill maybe, but as they say: Nuke it from orbit, it’s the only way to be sure.


Thank you.

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