Moment of Inetria of Payload attached


I am attaching a payload of irregular shaped object to tool_flange of the UR5 robot. When it comes to payload configuration. I filled up the payload mass and cog with respect tool_flange frame. Also there’s option to use custom inertia matrix. But a default one is calculated automatically.

Digging in the Manual I found that default inertia matrix is calculated considering a sphere of density 1g/cm3.

I am trying to understand, is there any performance difference between custom inertia or default inertia matrix for payload. It’s very difficult to get inertia matrix for a irregular shaped object. I am also curious too why sphere has been consider here for default inertia matrix calculation.

Thank you