DOP modify data before/after solver

[rayman]

I`m trying to store some sim data inside dops after solver and read it before sim in next sim step.

For example I want to create simple tool that changes Active Value based on average velocity.

I tried to create empty data and store the object position there, then apply sover data, then another empty data. The problem is that both of my custom data values are always the same. I tried using merge, apply data and multi solver (with sops solvers) in different configurations without success. Can someone give me some hints.

Thanks.

[bloomendale]

Houdini parses node graph two times - first looking for data and then solving it. So all your applyData DOPs will be before solve phase - and you'll get the same data.

Possible solution is to modify all data with solvers - multiple solver DOP with copy data solver dop which copies pos. info to some empty pos data chunk, then your rbd solver and then second copy data solver dop which again copies new pos data to another pos. data.

Another way is to copy Position data without solvers (using expressions and emptydata DOP, Modifydata DOP for example) and then rbd solver will change original Position data and you can compare it to your copied one BUT only in the next timestep (or using some kind of solver to compare you can do it in current timestep right after rbd solver).

Example image is only to demonstrate principles, cause you can access velocity right in Position data.

p.s. I'm new to Houdini so there are might be better ways)

[rayman]

Thank you!

Copy Data Solver with multisolver works nice!