Dear teacher
Thank you for your busy schedule to look at my problem.
Allows to introduce myself。
I am Chinese, and English is poor.So the terminology is inappropriate, please forgive me.
Admire your skill level in houdini.
I on in cmivfx Website buy a tutorial Houdini Network Relationships Vol 1.
There is a knowledge point do not know.
I understand the principle of this case.
First established in sop custom data field. Vel and density.
Then being transferred data to Dop ，Then Dop have two nodes: source_density, source_velocity,.
But this is not a local variable, such as vel and density. Dop in the pyro could believe that. mydensity is density source, myvel is' velocity.
Because OUT_vel the normal attributes?
Do not know that you can understand what I mean it.


Thanks again