# Godot / Jolt Physics and small objects (cm / mm)

4.2

### TLDR

I i use Jolt, Will there be problems in simulating small objects (3-4cm), and (2-4mm)

### Question

I am looking at building a small simulation of a mechanical process rig, that will use physics to simulate objects moving on a conveyer belt.

I have experiance in doing this in 3.x (I made : https://virtualplant.didacticservices.co.uk/)

My question is regarding small objects. Previously i didnt care about scale, as the simualtion was just a simulation, but here i am quite keen to get the scale right, as i will be working with imported CAD files.

The objects are â€ś3-4cm cansâ€ť that will be filled with â€ś2-3mm ballsâ€ť

• think mints in a mint tin for example

Will simulating at this scale cause problems?

Even the godot UI doesnt seem to cater for zooming in that small very well

Would i be better making everything 10x scale?

Thanks, but i searched docs already, and there is nothing on that page that specifically addresses size - it talks about â€ś5km distancesâ€ť and â€śsmall objectsâ€ť

Was wondering more if people had any actual experiance

All godot and blender measurements are in m, so it would seem to make sense to use accurate measurement

Ahh - I see :

Note that the physics simulation works best if you use SI units (meters, radians, seconds, kg). In order for the simluation to be accurate, dynamic objects should be in the order [0.1, 10] meters long and have speeds in the order of [0, 500] m/s. Static object should be in the order [0.1, 2000] meter long. If you are using different units, consider scaling the objects before passing them on to the physics simulation.

So this would indicate 0.1m - 10cm to be the smallest size that makes sense?

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