Fast way to draw an ellipse in a parallelogram?

Rhino
1

Hi all,

I’m trying to figure out the quickest way to draw an ellipse in a parallelogram. I’ve tried shearing and moving the control ponts… but for the amount i do it in my drafting workflow I wish there was a single command I could use or a quicker way to draw this kind of shape. Anyone have a good workflow for this?

Photo of what I’m talking about below:

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image1920×1200 185 KB

2

I can also add a few drawings to show what I’m running into. So the first one is how I try to draw a circle and shear it. But often it comes out too long to fit into the parallelogram in the way I need it to.

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image1920×1200 167 KB

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image1920×1200 168 KB

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image1920×1200 171 KB

Of course from this point I can manually move the control points and make it work, which is what I did for the original drawing, but this starts to feel like an inefficient workflow

3

how about gh?

ellipse_to_parallelogram__jvs.gh (16.4 KB)

4

Hi Jakob! Thanks for the script! How do you run it? I’m not super familiar with Grasshopper

5

post your 3dm

6

Ellipse Circle Demo.3dm (3.4 MB)

7

forgive my ignorance, but isn’t that simply a circle viewed at an oblique angle?

you could model this easily with a rectangle and a circle…

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image1175×754 58.4 KB

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image453×573 8.05 KB

9

Hi Kyle! Yeah, you’re right! It’s a circle viewed at an oblique angle. And I could definitely model it, rotate it to the angle I want, make2D, and I’d have the shape. But in this case I’m really just making an axonometric drawing without modeling anything, so I was wondering if there is an efficient way to draw this shape without having to go into 3D. I’m also doing a drawing where I have to do this kind of shape a lot: drawing wheels, push-buttons, etc, so having an efficient way to do it would save me some time. The fastest way I’ve found so far is to draw the circle and manually move the control points to the right places within the parallelogram, but this still feels like kind of a slow process and I’m wondering if someone has a quicker way… but maybe I’m in the minority using rhino for drafting without making a model…

10

run this in the gh-player - it will ask you for the geometry , click the parallelogram and get an ellipse in it

ellipse_to_parallelogram__jvsforPlayer.gh (18.7 KB)

11

How’s this?

12

I think this will be the best way! Thank you so much Jakob! I even set up a macro for it so it’s a one command, one-click workflow - much, much faster than what I was doing before!

13

Actually a bit clunky! I slimmed it down…

14

i like @jeremy5 solution best. ( the given circle can be moved and scale1d-ed)

just to add some nerdy workflow:
_curve Degree = 2
_insertKink 4 times
_changeDegree of corners to 1/sqrt(2)
:face_with_symbols_on_mouth:

have a nice weekend
kind regards -tom

16

I still prefer the grasshopper version because it’s basically instant, but here is a quick-ish workflow using shear and a custom scale1D macro set (provided below.) I do like the non-GH workflows because they can be used with any shape. Also thanks to Jeremy and Tom I realized the issue I was having was that I was shearing without scale1D-ing the object to the parallelogram. Thanks y’all for the workflows. This was super helpful :slight_smile:

Scale1DRight.py (1.6 KB)

Scale1DLeft.py (1.6 KB)

Scale1DBottom.py (1.6 KB)

Scale1DTop.py (1.5 KB)