Polytomizer Tool: Create Low-Poly Art from Your Images

What is Polytomization?

Polytomization is the computer-aided art form that takes a complex image and rebuilds it in triangles. Think of it like a mosaic, or stained glass. In a traditional mosaic, an artist places tiles to form a picture. But in this polytomizer tool:

• The Tiles (or glass pieces) are triangles of various sizes.
• The Grout is the math that connects them and cuts them to size.
• The Color is pulled directly from your original photo.

The Science Behind the Art

When you use the polytomizer tool, you are working within an algorithm. This entire process rests on the foundations laid by Euclid, the father of geometry. While the specific algorithm used here was developed by Boris Delaunay in 1934, the rules of the 2D plane, how points relate, how lines connect, and how triangles form, are pure Euclidean geometry.

Here is the step-by-step breakdown of what is happening:

The Vertices (The Dots)

When you paint with the brush, you are creating vertices. These are coordinate points $(x, y)$ that tell the computer, “This area is to be the vertex of a triangle.”

• High Detail: When you click many dots on an eye, you tell the computer to preserve that detail.
• Low Detail: When you scatter dots in the sky, you tell the computer to treat that area as a single, flat wash of color.

The Mesh (Delaunay Triangulation)

The computer takes your scattered dots and connects them to form triangles. It doesn’t just connect them randomly; it uses a specific rule called Delaunay Triangulation. This rule ensures that the triangles are as equilateral (“fat”) as possible, avoiding long, skinny slivers that look like glitches.

The Boundary (Corner Anchors)

To ensure your art covers the entire image, the tool automatically places anchor points at the four corners of your canvas. This means the triangulation always extends to the edges of your photo, no gaps, no missing corners. Every pixel of your image falls inside a triangle.

The Rendering (The Color)

Once the triangles are drawn, the computer looks at the original photo hidden underneath. It finds the centroid of each triangle, the average of its three vertex coordinates, samples the pixel color at that exact point, and fills the entire triangle with that single color.

See an example of low-poly art styles in my low-poly Valentine’s Heart post.

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How to Use It

• Upload: Click “Upload Image” to select a photo from your device.
• Paint Your Points:
  • Brush Mode: Click and drag over the image to place points. Set Density to “1” for precise, single-dot placement — great for eyes or details. Set it higher (5-10) to scatter many points quickly for backgrounds.
  • Fill Mode: Click or drag to flood an area with evenly spaced points. This is the fastest way to cover large areas. Adjust the Size for the brush radius and the Density for how tightly packed the points are.
  • Eraser Mode: Click and drag to remove points within the brush radius.
• Polytomize: Click the “Polytomize!” button to connect your dots into a mesh of triangles.
• Refine: Not happy? Use the Eraser to remove points, or hit Undo (Ctrl+Z) to step back. You can keep adding or removing points and clicking “Polytomize” again to update the look.
• Save: When you are finished, click “Save PNG” to download your masterpiece.

Tips for Best Results

• Eyes and Faces: Use a small brush size and a Density of 1 to manually click around the eyes and lips. This preserves the most important details.
• Backgrounds: Use a large brush and high density, or switch to Fill mode, to quickly cover the sky or background with large, abstract triangles.