[krihamm]

I have a 3D body aligned with the z-axis. When I created the geometry of the body I started with a sketch in the ZY plane, revolving and extruding in positive z-direction. After that I created new planes and sketches and extruded in the negative z-direction. The finished geometry is thus extruded in both positive and negative z-direction relative the original ZY plane.

For calculating the center of pressure of the body I use the expression:

areaInt(Z*Pressure)@Body/areaInt(Pressure)@Body.

I get a negative value. Is the reference point from the top of the geometry or the original ZY plane, i.e. not the top of the body but some distance below it in negative z-direction? If that is the case I need to take that into account when deciding the center of pressure since the top part wouldn't be accounted for.

Of course the most logical answer would be that the center of pressure is calculated from the top of the geometry, but asking just to be sure!

Thanks!

[ghorrocks]

It is referenced to whatever your z axis is referenced to. That is probably the coordinate system 1, the defaults.