HurricaneTutorial 03
Cloth Tearing Simulation in Blender with Water
Tear a cloth exactly where you want while water falls on it: Cloth preset, Surface Collision, a painted Split mask, Weld constraints that break, and a mass balance between cloth and liquid.
In this tutorial we build a cloth that holds a ball of water, stretches under its weight and then tears along a line we paint ourselves, letting the liquid pour through the opening.
You will combine two emitters in the same solver (a cloth and a liquid), make them collide correctly, control the tear with a vertex-painted mask and Weld constraints, and finish by generating a clean cloth surface.
Step by step
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In Add Emitter choose Sphere Volume. Make the sphere a little smaller, apply the scale and move it close to the plane. Set it to emit from frame 1 to 7 and lower the Resolution to 0.035: a lower value generates more particles. If you play it now, the water goes straight through the cloth — we fix that next.
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When you mix different emitter types you have to set up their collisions. In Simulation → Deformable Surface enable:
- Surface Collision: builds a virtual collision mesh over the cloth so the particles detect its surface and collide with it.
- Surface Self Collision: when the cloth tears, the tension can make it fold violently over itself; this keeps it colliding with itself and behaving realistically.
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Some particles still go out of control: in Simulation Settings raise Substeps Max from 5 to 7. They also bounce too much on the floor: in Colliders, raise the floor's Damping to 0.99. With this, the base simulation works.
Damping 0.9 vs 0.99
The video compares both values side by side: at 0.99 the liquid settles on the floor instead of bouncing and scattering.
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Temporarily disable the water to work only with the cloth. Instead of a random Voronoi pattern we want a fully controlled tear, so we paint it: in Object Data Properties → Color Attributes create a new attribute named
split, switch to Vertex Paint (the mask starts black) and paint white where the tear should happen.What the Tools section is for
In Particles → Emitter → Tools you can generate masks over the geometry to control different areas of an emitter: different viscosities in parts of a fluid, or different behaviours in parts of a cloth.
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In Tools, add Mix Attributes, change its mode from Multiply to Add and set Attribute 1 to
split. Use the tool's eye icon to preview the mask. Then add a Split tool and, in its Attribute field, type the output of the mix:mix_attributes. The Split now knows which area to separate.Leave the preview before simulating
Click the tool's eye icon again to exit the visualization mode; otherwise you cannot continue with the simulation.
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With the water back on, the cloth tears too early. You could raise Max Elongation Ratio, but too high and the cloth will barely tear at all. A better balance comes from mass: in Main Settings, give the plane a Mass of 4 and the sphere particles a Mass of 0.7. The cloth now holds the water long enough and still tears when the pins pull it open.
You now have a cloth that tears exactly where you painted it while interacting with the liquid. Upcoming tutorials will go deeper into these tools and other ways to control this kind of simulation.