make grid into sphere

 

MAKE THESE NODES PLUG THEM IN BLAM
just in case the image is dead, assuming a grid lying on XZ plane
A loose relbbox with "input" set to "First Input", plugs into a vecToFloat.
The X and Z outputs plug into the U and V of a fromPolar.
Output of fromPolar goes into a Multiply. A loose makeXForm goes into 2nd input of the multiply.

Output of Multiply goes into the GeoVopOutput P input.

I think this post explains a bit more about how this works, but the rough dummy explanation is that you're making "sort of UV coordinates based on the position of your grid" (hence the relbbox), then you move your points to the uv of the target object.

https://www.sidefx.com/forum/topic/60740/?page=1#post-272057

 

flickering pyro - especially after converting particles to vdb

 Say you've made some nice particles and you give them density/burn/temperature and then convert these to VDB fields. You might find they flicker ever so slightly during rendertime. This is to do with a changing grid size. The "fix" is to make a gigantic box shaped VDB that encompasses the area of your particles/sim and plug this into the second input of the VDB from Particles node. Now the grid is fixed and you shouldn't have any more related flickering!

Pro tip from Walter.