Depth volume voxel size info missing in RBD material fracture

[archz2 1]

I am fracturing a sphere and learning about fracturing from this tutorial. 

At 15 min 33 seconds, the tutor has information about depth volume voxel size for the detail panel of RBD material fracture.

 

However at my end, I am not having any such feature. How to enable it?

 

The documentation for 19.5 also mentions about voxel size in this node but I'm not having it. 
https://www.sidefx.com/docs/houdini/nodes/sop/rbdmaterialfracture.html

Edited August 1 by archz2