Organic Blob Shape Generator

Smooth, irregular blob shapes have become a defining visual element of modern web design, sitting behind a hero headline, framing a product screenshot, or adding organic movement to an otherwise geometric layout. Hand drawing one that actually looks natural, rather than lumpy or obviously computer generated, takes real practice with a pen tool. This tool generates a randomized, smooth organic shape as clean SVG path data instantly, with a one click regenerate option to explore fresh variations until one feels right.

The idea behind a computer generated blob

The underlying approach starts with something perfectly regular, a set of points spaced evenly around a circle, and then deliberately perturbs each point's distance from the center by a random amount. Rather than a perfect circle, you get a shape that bulges outward here and pinches inward there, in a way that reads as organic rather than mechanical. The key is what happens next: the perturbed points are not simply connected with straight lines, which would produce a jagged, star-like polygon, they are connected with a smooth curve that flows through every point, which is exactly what turns a set of random points into a shape that looks like it could have been drawn by hand.

How the smooth curve is actually built

This tool uses a Catmull-Rom spline, a well established curve interpolation technique, to draw a smooth path that passes through every one of the randomized points exactly, unlike some curve fitting methods that only approximate a set of points. Each Catmull-Rom segment is converted mathematically into an equivalent cubic Bezier curve, since Bezier curves are what SVG path data natively understands, meaning the resulting path is standard, clean, hand-editable SVG syntax, not some proprietary or unusual curve format. The blob closes into a continuous loop by wrapping the point sequence around itself, so the curve flows seamlessly from the last point back into the first with no visible seam.

Complexity and irregularity control the character of the shape

Two settings shape the final result. Complexity controls how many points the blob is built from, fewer points produce a simpler shape with broader, sweeping curves, while more points allow for finer, more intricate bulges and indentations around the edge. Irregularity controls how far each point's radius is allowed to randomly deviate from a perfect circle, a low irregularity produces a gentle, barely-there wobble close to a circle, while a high irregularity produces a much more dramatic, unpredictable silhouette. Together these two controls span the range from a subtle, professional background accent to a bold, highly organic focal shape.

Common places a blob shape gets used

A blob commonly sits as a colored background shape behind a hero image or headline, adding visual softness and depth to an otherwise flat section. It also works well as a clipping mask for a photo, giving a product image or portrait an organic, non-rectangular outline instead of a hard-edged crop. Layered at low opacity, several overlapping blobs of different sizes and colors create a soft, ambient background texture, a popular pattern in modern SaaS and portfolio site design.

Runs entirely in your browser

Every blob is generated instantly using plain JavaScript math, nothing is sent to a server. The generated shape is standard SVG path data, so once you have one you like, our SVG Code Editor is a natural next step for combining it with other artwork or fine tuning individual points by hand, and our SVG Gradient Generator pairs well if you want the blob filled with a gradient instead of a flat color, both part of the same SVG & Design Tools collection this tool belongs to.