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SVG Blob Shape Builder🔒 100% local
Generate organic blob shapes as SVG paths. Perfect for backgrounds, illustrations, and design elements.
Complexity (Points)
Growth Factor
Base Radius
Seed
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Generates an organic blob as an SVG file from four controls: how many points the outline has, a growth factor for how far each point may bulge, the base radius and a seed. Point distances come from a small linear-congruential generator started at the seed, and the points are joined into a closed path inside a fixed two-colour SVG wrapper.
How to use it
- Set Complexity between 3 and 20 to choose how many points the outline has.
- Set Growth Factor between 0.5 and 3; higher values make the radii vary more and the outline spikier.
- Type a seed or press Randomize Seed, then press Generate Blob.
- The shape is previewed in a square, with the SVG source underneath for copying.
Worked example
seed 1, complexity 5, growth 1.5, radius 100becomes<svg viewBox="-120 -120 240 240" xmlns="http://www.w3.org/2000/svg">
<path d="M 100 0 L 17.4 53.5 L -56.7 41.2 L -48.6 -35.3 L 29.8 -91.9 L 83.5 -0.0 Z" fill="#0A0F2C" stroke="#CC2B22" stroke-width="2" fill-rule="evenodd"/>
</svg>The same numeric seed with the same sliders always produces this exact path. The fill and stroke colours are fixed by the generator.
When to use it
- Making a background shape for a hero section without opening a vector editor.
- Producing variants of one blob by changing only the seed.
- Getting a single self-contained SVG element you can paste into markup or into a CSS background.
What it does not do
- Only the numeric part of the seed is used. A label such as logo-v2 fails the numeric parse and falls back to the current timestamp, so it will not reproduce a shape.
- Points are joined with straight line segments, so the outline is a polygon - at low complexity the flat edges are visible. There is no curve smoothing.
- Fill, stroke and stroke width are hard-coded in the output; you have to edit them after copying.
- The seed box starts as the page-load timestamp, so pressing Generate Blob twice without touching it gives two different shapes.