Sampling point attributes for volumes

[IhabAli]

Hello,

I'm trying to build a setup that would move volumetric noise along the spine of a sweep object, effectively changing the coordinate system of the noise to be based on an object, at least in 1 axis. I set this up using the following simple network:

Inside the volume VOP I'm finding the nearest point to the voxel and getting its curveu parameter value

Problem is I'm getting this strange quantization in the volume for some reason 

 

Even through the curveu on the points appears smooth:

 

I checked 3D texture and visualization settings but they don't seem to have any effect so I'm fairly certain this is not a viewport issue. 

 

 

Any idea what's happening?

 

Regards,

IA

 

 

Edited September 26, 2019 by IhabAli

[StepbyStepVFX]

Can you show your importpoint1 node parameters inside the volumevop ? Is it also connected to the second input ? Do you retrieve the right attribute ?

Also, try to render a mantra frame of it, to check it is not a viewport issue.

last but least in your vdbfrompolygon, did you check fog vdb with fill interior ? And is you mesh closed / airtight ?

[IhabAli]

Thanks JO. Not much going on with import point it's basically just the point() vex snippet and I'm retrieving the attribute I need. Mantra appears to render this smoothly but the view port would also render smoothly a volume that is sampled directly from the position of the voxel(e.g. with a volume wrangle or vop that basically does @density=@P.y in the case of my example) I'm not sure I understand why this particular method of sampling the attribute and assigning to the voxel causes view port issues. 

 

Edited September 28, 2019 by IhabAli

[IhabAli]

I actually found the culprit right after I submitted my reply

 

HDR textures under 3D was not set to full HDR (it was at 8bit). For some reason that displaying banding with this particular attribute sampling method.