This is simple...but I'm a bit dense right now

I know this is simple to do…but my brain isn’t working. Can someone just remind me:

I have this geometry:


and I want to create the same exact geometry 1/4 of an inch bigger.
Offset will round the corners:
image
Which is not what I want…I want the corners to be equally sharp as the original shape.
Scaling the object does not keep the right proportions…I can’t control the 1/4" and it won’t align back when I try to center the objects on a common center point:

What do I do?

In Carbide Create, if one wants sharp corners, the geometry has to be created at the largest size and then only reduced.

you can either:

  • export to an SVG, do the offset in a 3rd party tool and re-import
  • re-draw the geometry at the larger size — is the curve an arc of a circle?

If you’ll post your file we can look into this with you.

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That actually makes me feel better! I’m not as dense as I thought :slight_smile:

I’ll do it in another product and bring it back. no issues.

Thanks.

Wouldn’t scaling the image by .250" keep the corners sharp?

You can’t scale by a fixed dimension. You can scale by a percentage, or change one dimension by a fixed number, but the other dimension will be changed by the same percentage as the first.
So, yes it would keep the corners sharp, but it would not offset the entire boundary by 0.25"

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I did what I had to do…brought it into Inkscape and offset it there. Still required a little boolean magic when I got it back into CC, but it did scale it the way I would have expected it.

I noticed a couple of things…
If the object is symmetrical, it can be expanded using the scaling tool.
image
However, if it is not, Scaling distorts the image:

I’m guessing it’s the mathematics of scaling…but it doesn’t actually make intuitive sense to me.

Then there is the magic of “Offset”. Apparently, if you offset the SAME amount inward and outward, the results will preserve the sharp edges:
image
Results in:

and if you then delete the original object, then offset back in by the same amount:



Your hard angles are back.

Turns out this is the case even if you ADD UP TO the same number:
image
Outward by 1"


Inward by .75" (Rounded angles continue)

Then - Inward again, by the remaining .25"

Your hard angles are back!

I guess it’s the math that makes this happen…but it surely is strange behavior.

If you have a rectangle that is 1" x 0.5", and you scale it by 50% (x 1.5) you will add 1/4" to each end.
But you will only add 1/8" to the longer sides.

image

Each dimension is multiplied by 1.5

To get a constant offset you would have to scale the length by 1.5, and the width by 2
This is one possible answer, give us non-proportional scaling so we can enter different values for X & Y.
The other option would be to add extended corners in offset, rather than rounded corners.

This would not be a perfect solution, as what would likely happen in the corner by the convex end is a tangential extension (blue) rather than a natural extension of the curve (red) until it intersects the other extended sides

This might be close enough???

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In this case, yes…it would have been close enough.

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