Suddenly simulation becomes very slow

James

It usually not this slow

even the

Simulating...
Initializing Simulation..

took 3 mins

not including the simulation which only 15 frames

took 10 mins

I know this is not normal, cos I simulate often in the same scene.

rtx 4070ti 12gb

what could be wrong?

felis

One or more very dense meshes?

Do you get many springs that violate collision distance?

What are you trying to simulate? 

crosswind

Under some circumstances,  e.g. when there're quite a few dForce items with Enable Smoothing - On, improper settings on dynamic surfaces, or more collisions on poly, edge and vertex (Collision Mode - Best), simulating with Timline with more Inititialization Time will take much longer in terms of total simulation time. Pls check...

If it is the same scene, same dForce items and same settings, it took 3 mins to simulate yesterday but 13 mins today... THAT is an odd thing....

Richard Haseltine

My suspicion would be that it is, as I think felis was suggesting, a lot of edges thata re shorter than the Dynamic Offset value - listing those can take a while (and DS doesn't process thee vent queue while it is doing so) and then the fight between the rest-length of the edges (which act as springs during simulation) and the minimum offset keeps pumping energy into the simlation making it 9at best) slow to settle. If you have the progress bar expanded you should see the messages relating to this, and they will also be in the log file (Help>Troubleshooting>View Log file). If that is the issue then, depending on the degree to which the edges are too short, you may be able to improve matters by lowering the dynamic offset value in the Surfaces pane (but you may then need to adjust the collision detection settings to avoid poke-through, with its own speed penalty).

James

I found out the problem.
Somehow I keyframe a wall accidetanly, It gets moved.
Although not sure why the wall makes everything slow.

But I took out the keyframe and all back to normal.
Thank you all.