Hi all,
I'm trying to look into using isosurface rendering of VDBs rather than take the extra step to convert them into polygons. In doing so I have ran into an odd problem. Whenever I use a VDB From Polygons node and add a surface attribute to it, the isosurface render fails.

I have attached a hip file to show this. With the vdb_from_polys_normal output flag set you can see the render is normal. If you then activate the display flag on the with_surface_attribute node, the render will show nothing at all.

Is this normal? Admittedly I cannot find out how to use the volume surface attributes, but I'm thinking it should still render. Maybe a bug?

Note: in the shopnet1>iso I enabled the isosurface rendering by adding the vm_volumeiso and vm_volumedensity properties.

Is your current material is taking density into account? Try dropping a billowy smoke volume based material onto the object and it will render. I would probably just drop down an isooffset followed up by a ConvertVDB.

Hi Enivob,
I'm trying to render an isosurface as a solid - not as a volume. In the example file, if you immediately go to the render view and hit render you'll see an isosurface, as seen in the attached image. Ignoring the weird dark patches in the render for now, it renders correctly. But if you set the output flag from the ‘vdb_from_polys_normal’ node to the ‘with_surface_attribute’ node, then nothing renders. The only difference between those two nodes is that ‘with_surface_attribute’ has a surface attribute set. This shouldn't stop it from rendering as far as I know.

Hello sir,

If you name your vdb attribute, it seems to render as you expect.

-jez

Hello to you sir!

How bizarre. For the VDB Name the help states ‘leave this blank to use the attribute name’.
Also, if you set VDB Name to be anything that does not start with a ‘v’ then it will not render.
It seems very bugworthy, so I submitted it (#76719).