# Wind pressure on building facade

Hi everyone

I’ve got a few questions about applying wind load to a building structure.

This is what I have, pressure values at the center of each mesh face, which I want to group, add up and move to certain points of building structure.

What confuses me is:

1. How to add them up if there are both positive and negative pressure values? As absolute values? And how to determine the sign of such sum?

2. What would be the direction of those sums? Perpendicular to building facade?

3. How to define the orientation of those pressure values? Positive pressure acts towards the building, while negative one acts away from it?

Thanks

Hi Stefan,
Each mesh face has an individual value for the wind pressure - positive (pressure) and negative (suction).
If positive, the force on the mesh face will act towards inside, if negative, then towards outside, always in the orientation of the mesh face normal vector.

I am not sure how do you want to group them, though.

Thank you.

In the end I just grouped forces by the proximity to the points on the structure and used mass addition to add them up as vectors.