Archived

This topic is now archived and is closed to further replies.

stepsize of ODE

This topic is 4956 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Could anyone please tell me what "stepsize" in dWorldStep of ODE actually means. Is it simply time step ? or something else... I made a demo using ODE and in the dWorldStep if i use the frameTime as stepsize, the simulation runs awefully slow, almost as if itz running in super slow mo :S. But the mass, the forces and the overall system configuration is such that it should not be running that slowly in real life. I used -9.81 as gravitational acceleration and etc. How do i make ODE simulation FPS independent and at the same time making movement speed realistic ?

Share this post


Link to post
Share on other sites
It''s the time interval (in time units) between successive calls to dWorldStep. In ODE, if 1 unit of length=1 metre and 1 unit of mass=1 kilogram, then 1 unit of time=1 second.

You''ll want it to be small - about 0.01 or smaller for decent accuracy.

Share this post


Link to post
Share on other sites
I can''t really contribute, I just had a question to ask.

I thought that ODE stood for Ordinary Differential Equations, and was math terminology. Now it seems like it''s some physics engine that I have not heard of. What is it?!

Share this post


Link to post
Share on other sites
Then why on earh would my demo run differently ( with different speed) on different machines.. :S. Am calculating the frame time in seconds.. and everything is in standard units ( meter, kg, sec ). Plus, i got one more confusion.. if the ''stepsize'' of dWorldStep was really time then putting in a 0 should practically pause the simulation right ? BUT THAT doesn''t happen rather the system becomes toooootally unstable and BODY position becomes infintity... as if something was divided by 0 !!!

Share this post


Link to post
Share on other sites
browny:

if you want to pause the simulation dont call worldstep...I''m not sure why passing a 0.0 wouldn''t pause it, but it seems like if you really want to pause the simulatioin you shouldnt call worlkd step at all...this is more efficient anyways


neko

Share this post


Link to post
Share on other sites