How to apply a SIM_Force

[narthe]

Hi guys,

 

i'm trying to apply a force on the points of a geometry.

So far i have a DOP network where i retrieve my geometry and its points, i give these points a mass and a velocity in my solver i'm coding.

Then i add a gravity node.

I read this article in the documentation : http://www.sidefx.com/docs/hdk13.0/_h_d_k__op_basics__sim_solver.html#HDK_OpBasics_SimSolver_ExternalForces

that explains how to retrieve the forces in the DOP network but then how can i apply them to my points?

Tell me if you need more informations.

Thanks.

 

[narthe]

I'm now wondering what's the difference between getForce() and applyNoise in the SIM_Force class.

I'm guessing that i should use applyNoise if i want to apply a force on my points.

[ikarus]

When you say apply this force to your points do you mean you want to integrate their velocities/positions according to the force?

[narthe]

When you say apply this force to your points do you mean you want to integrate their velocities/positions according to the force?

Yep that's exactly what i want to do

[narthe]

I tried using the getForce() function on each of my points. So now i retrieve the force as a vector that is equal to (0.0, -9.80665, 0.0) wich is exactly my gravity so it's great.

I guess i have to apply this force on my own on each of my points according to the timestep or the framestep.

[ikarus]

A basic euler integration would be

vel = vel + force/mass*timeinc
pos = pos + vel*timeinc

i think the hair solver example in hdk does this if you want an hdk oriented code

[narthe]

Thanks! i almost did the same but forgot to include the mass of my particules