Scaled objects do not change physical properties?

Omniverse Isaac Sim
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The forces/torques required to move a scaled object does not seem to change. I have attached a video with a standard cube and a scaled cubed. It can be seen that it requires same force to move both cubes. How do I scale the physical properties with the same amount as the visual? Changing e.g. the mass does not seem to have an effect.

Thanks

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Hi @thokr19 - In physics-based simulations, scaling an object’s visual representation does not automatically scale its physical properties. This is because the physical properties of an object, such as its mass, inertia, and friction, are often defined separately from its visual properties.

If you want to scale an object’s physical properties in Isaac Sim, you’ll need to manually adjust these properties. Here’s how you can do it:

  1. Mass: You can adjust the mass of the object in its physical properties. If you scale the object’s size by a factor of k, you might want to scale its mass by a factor of k^3, assuming a uniform density.
  2. Inertia: The moment of inertia of an object depends on both its mass and its shape. If you scale the object’s size, you’ll need to adjust its moment of inertia accordingly. The exact adjustment will depend on the shape of the object.
  3. Friction: The friction between the object and other surfaces might also need to be adjusted when you scale the object. This will depend on the specific physics of the simulation.

Remember that these adjustments might not result in a perfectly scaled behavior, due to the complexities of physics simulations. You might need to experiment with different values and observe the results to get the behavior you want.

1 Like
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It makes perfect sense. I’ll try it.
Thanks