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I am working on a character scene and I want them to have dynamic clothing. While working on this I suddenly realized that the character is gigantic in scene units, about 47 feet high! The cloth simulation is acting a bit "light", as if it were made of tissue paper, but it is not slow. I would like to verify whether cloth simulations act differently based on the size of the object in the scene, or if i just need to change some settings to make the cloth have more weight and to wrinkle less (I am going for a leather type material).

Scaling the scene down to real-world size is not an option because it breaks self-collisions in the cloth, as some of the geometry is below the minimum distance I can set the self-collision distance to, causing the cloth to "explode".

Sorry if this a noob question but I am very new to cloth simulation in Blender and don't know what all the settings do.

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    $\begingroup$ I'm not sure about the scene units, but to make the cloth more like leather, increase the stiffness value. $\endgroup$
    – Millard
    Aug 27 '19 at 0:14
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Yes - size will significantly affect all of the physics simulations. Of particular interest will be the acceleration due to gravity; by having a 10x too large scene you are effectively applying only 1/10th of the force of gravity (which could explain the tissue-paper behaviour of your cloth).

Quick solution would be to adjust the scene gravity by a suitable factor to account for your increased scale (eg, change from -9.8m/s to -98m/s for a 10x change in scale). However, you might still get it behaving a bit oddly since any stiffness and weight will be similarly affected by the scale.

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Yes, the cloth simulation parameters and precision depend on the scene units. And that doesn't mean the object scale, that's obvious to get a different result. But it means the scene unit scale, scene properties > units > unit scale.

An object with the same size but different unit scale will get different results in the cloth simulation. More precisely, a unit scale of 0.1 is ideal for a human sized figure, while with 1.0 or 0.01 the cloth simulation will get bad results.

unit scale

Please note that the scene units don't affect the objects size, so camera perspective and light falloff will work fine. On the other side if you scale objects out of their real dimensions then you break them.

Then that the cloth precision depends on scene units is not good in my opinion, but I'm not sure this could be addressed as a bug.

edit. This is related to Blender 2.92.

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