I set time interval 0.1s in output tab.The finish time is 20s. But when I load the result file, only 10 time frame in there:0s,2s,4s,6s,...,18s,20s,so the time interval is 2s,why? Thanks

I would guess you set the plot time interval for "selected data," and you are looking at the "restart" output.

Restart output defaults to plot every one-tenth of the total simulation time which is 2 seconds for a 20 second simulation.

Under the analyze tab, change the "data source" from "restart" to "selected" and render the plots again.

I got it, thanks!