Deborah R. Fowler
Houdini - Packed
Posted Sept 2 2022
Updated Sept 2 2022
packed primitives - a houdini construct to more efficiently deal with geometry. Packed geometry makes it more efficient, faster, less memory. The packed piece makes it into an object entity that has orientation and location, you can use the pack and unpacked. It is like getting instancing for free. I strongly recommend you read the following document.
So what did we use before packing? Instancing. Instancing is still important for a number of reasons:
- you cannot copy and pack lights but you can instance
- renders that do not understand packed primitives (such as Arnold) would understand instances
- as we move to solaris/karma the copy to points node, really is just an instance node in disguise
Get used to using packing. It is a must. Be careful not to double
pack. Lost your materials? No worries - don't unpack, check first
that you have taken the steps outlined in the troubleshooting
guide
Mantra and Redshift respect packed geo.
When do you not want to back? When you are trying to use a boolean
for example. Think of it as a suitcase - if pack things up in a
suitcase, you have them, but you don't have access to them until
you unpack. If you are feeding geometry to a boolean, if you pack
you are hiding the details needed to manipulate the geometry. Pack
after using a pack node.
The checkboxes on the copy node family are great! Just a checkbox and your display/workflow improves substantial but there are separate pack and unpack nodes. Look for the "Pack and Instance" box.
Use a pack node vs the checkbox if you want to transfer
groups for example.
This has been the preferred workflow since the introduction of
"packed primitives" in Houdini 13. However, instances still are
functional but packing is robust. For instanced lights see my
section on lighting on the Overview page. In particular,
Although instancing can be used for geometry, packed geometry is preferred. However if you opt to use HtoA you may need to switch to instances.