What are volume and iso offset sops

[sadhu]

Hello there, want to know what are volume and iso offset sops. I didnt understand much through help documents. I want to know how both of them functions? What is their use or how to use them (I can guess as it is applicable to other sops, these two sops can be used in different ways. So even a hint will do)

Thanks

[pclaes]

They provide you with ways to generate volumes. Either directly as a block of volume (volume sop) or by calculating a volume from a mesh, a pointcloud, another volume with different algorithms to compute the volume (iso-offset). The isooffset can also create a surface mesh out of an incoming volume.

Volume are very useful tools for modeling, or scattering points in the volume or feeding it into sources for fluids.

You should do a search on this forum for "volume sample from file" or "volume gradient from file" to see some of the things volumes and sdf are used for. You might want to search for "signed distance field" (sdf) too - as that is often more useful than a plain volume.

[Macha]

Isooffsets are wonderful things! Perhaps my favorite Houdini bit!

If you generate an sdf you can quickly find out how far something is from a surface, so you can shrink or grow things, see if other geometry bits are inside or outside another geometry, create stable and robust collision objects. With volumes you can also store scalar or vector fields, both of them useful in simulations. One of the biggest benefits of volumes is that they are a robust way to pass around data, and it doesn't have to be hires (for example you can pass velocity vector fields to particles pops and get away with comparatively low resolutions)

Edited December 29, 2010 by Macha

[sadhu]

Thanks a lot Peter and Macha for this explanation