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RealFlow | Cinema 4D uses an internal proxy representation of a collision object – the so-called collision geometry. In order to refine this proxy object you have to add a → "Volume " tag and decrease → "Cell Size" or choose a higher better → "Collision Geometry Detail" option. You can also control the shape and look of the poxy through the → "Collider" tag's "Show Collision Geometry" option.
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