# Compute forces over an area on a moving boundary

Hi Guys,

Is there a way to compute forces over an area (circle or rectangle) on a moving boundary instead of computing for whole boundary.

Thanks

Hi Guys,

Is there a way to compute forces over an area (circle or rectangle) on a moving boundary instead of computing for whole boundary.

Thanks

## Comments

You can choose the particles you want to compute the force exerted by the fluid using different selectors... such as "mk" lable, type of particles, but also the Id. Therefore if you know the Id (particle number) you can use "onlyid:XXX-XXXX"

Regards