when i want to render a animation, V-Ray says “please wait for the current render to finish” what to do?
Please make sure you’ve enabled the Batch render setting (V-Ray Render Options > Global Switches under Misc.). In order for V-Ray to allow batch rendering you need to have that checked.
tanks if i want to slow down the hole animation? How to do that?
By adding more ticks in between the keyframes.
For example if you have an animation going on from tick 0-50, if you change it to be between tick 0-100, it will take twice as long.
To spread out the keyframes over the timeline you can use for example the BongoScaleKeyframes command, more info can be found here: http://bongo.rhino3d.com/page/timeline-1
When you render the video, you can also affect the time/speed. The more frames you render the slower it will be. If you have an animation of 100 ticks, you can output it as 101 frames (using 15 fps) then you get a 6 seconds long video, or you can output 900 frames (using 15 fps) and the same video is 60 seconds long.