Solved Slow Python in R20 ?


working with thinking particles controlled via python seems to be much slower in R20 as in earlier versions. I have a simple test file attached: in the xpresso tag 10000 particles are generated and in the python tag the velocity of each particle is read and set again (makes not much sense ... just for testing purpose).

In R19 I get about 100 fps in the viewport after all 10000 particles are generated.
In R20 I get only about 20 fps :-(

Especially the SetVelocity command makes the difference: in R19 the fps is nearly the same (100 fps) with or without the SetVelocity command. In R20 I get the 100 fps without SetVelocity and it drops to 20 fps with SetVelocity. (??)

Are there any R20 settings that I missed in order to get the same speed as in R19 ?



Hi, @ruckzuck, thanks a lot for bringing us such a case.

While I was able to reproduce it the first time I tried it. Now, I'm not able and I do have the same fps count from R20 than R19 while I didn't touch the file.

So does the slowness happens all the time or just some time?


@m_adam said in Slow Python in R20 ?:


Hi Maxime,

thanks for trying to reproduce this behaviour.
It's strange that you can see this speed difference only the first time. I can constantly see the low fps in R20 :-(
Today I also checked the speed in R18: here it's the same speed as in R19.

It's interesting that reading values from thinking particles via python seems to have no significant impact to the speed (at least it's the same effect as in earlier versions) - but when I try to set any values (like "SetVelocity"), the speed drops drastically in R20.


After a reboot, I'm able to reproduce it again...

I will create a bug report and more testing after Season's Greetings & SDK Team Vacation.

Anyway thanks a lot.