I drew my cat’s portrait using Desmos Graphing Calculator

Htoo Pyae Lwin
3 min readApr 30, 2023

Desmos Graphing Calculator is an entertaining tool to play around with. You can do lots of incredible pieces of stuff with it. I saw many people doing crazy things like animation and drawings using a whole load of Mathematical formulas to achieve. So I decided to join as well but I’m not a math genius so I had to look it up which equations are suitable to use.

So this is my cat, she’s a Sphynx, and her name is JoJo, (yeah from JoJo’s Bizarre Adventures 😂). She’s the cutest yet most evil little thing in my world.

JoJo

How to draw in Desmos

To draw a shape, start by typing in an equation that corresponds to the shape you want to create. For example, to draw a circle, type in “y=sqrt(r²-x²)” for the top half of the circle and “y=-sqrt(r²-x²)” for the bottom half. You can adjust the size and position of the circle by changing the value of “r”. To draw a rectangle, type in the equations for the four sides of the rectangle and adjust their positions and lengths as needed.

You can also draw other shapes, such as triangles and ellipses, by using appropriate equations. So the main thing you need to know is which equations to use.

To make things easier, for drawing static images, you can import an image and place it on the canvas. Then, you just draw using equations to align with the image, which is exactly what I did. I looked up a Sphynx Cat portrait on the internet that looks just like my cat and started to draw from there.

Which equations to use

The eyes, they’re circles, so I used the circle equation which is:

circle formula

And for the rest of the curves, you can either use Bezier Curve or the quadratic formula which is the one I used here.

quadratic formula vertex form

And yes, the rest is just finding the right values to draw the right curve based on the image on the canvas.

So what is this about?

I dunno, I thought it was just fun to do. If you’re reading this, I hope you play with it too. There’re so many cool pieces people have done with this tool and I’m really impressed with their crafts and they inspired me to try doing it even tho I’m not a Math genius.

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