I'm trying to connect some fluid cache to the whitewater source and I'm getting the error:


Error Invalid source /obj/whitewater_cource/whitewatersource1/vdbactivatesdf1 Error: Unable to evaluate expression ( Traceback (most recent call last): File "", line 5, in expression File "C:/PROGRA~1/SIDEEF~1/HOUDIN~1.383/houdini/python3.7libs\hou.py", line 18368, in intrinsicValue return _hou.Prim_intrinsicValue(self, intrinsic_name) hou.OperationFailed: The attempted operation failed. Invalid intrinsic name (/obj/whitewater_cource/whitewatersource1/vdbactivatesdf1/halfwidth))..
In fact, I get that error no matter what I hook up to the whitewater source. Any ideas what that could mean?

Thanks

(Houdini 19.0.383, Windows 21H2)

It looks like a typo. whitewater_course? Did you rename your whitewater_source node to whitewater_course by accident? Locate that expression on vdbactivatesdf1 and try correcting the typo in the expression?

hey hypernormal, did you figure out a solution to this?? I am getting the same error when I'm trying to cache a white water source. The error: whitewatersource1/vdbactivatesdf1/halfwidth)).. I'd really appreciate any help!!

I debugged some similar errors, for anyone else who encounters this in the future:

Invalid source /obj/geo1/whitewatersource1/vdbactivatesdf1
Error: Unable to evaluate expression (
Traceback (most recent call last):
File "<stdin>", line 5, in expression
....
/houdini/python2.7libs/hou.py", line 18395, in intrinsicValue
return _hou.Prim_intrinsicValue(self, intrinsic_name)
OperationFailed: The attempted operation failed.
Invalid intrinsic name
(/obj/geo1/whitewatersource1/vdbactivatesdf1/halfwidth)).

and

Invalid source /obj/geo1/whitewatersource3/vdbactivatesdf1
Error: Unable to evaluate expression (
Traceback (most recent call last):
File "<stdin>", line 4, in expression
IndexError: tuple index out of range
(/obj/geo1/whitewatersource3/vdbactivatesdf1/halfwidth)).

Since the main error was "Invalid source", I checked the inputs to the Whitewater source node and found no "surface" and "vel" VDBs.

Substituting a simple setup, wired into Input 1 of Whitewater source, eliminated the error message (though it's so simple that it doesn't produce a result) and confirmed that it was the lack of correct VDBs that caused this case:
Grid -> Scatter -> Particle Fluid Surface -> VDB from Particle Fluid (change the Output Name parm to "surface") -> Whitewater source.

Looking upstream in the network, another problem was found that caused the VDBs to not be generated for some frames and not give Whitewater source the "surface" and "vel" it was expecting.