writing alembics for maya - path attribute

Covered this in an older post, but this is for more straightforward cases when you want to define a group and shape node name for Maya purposes. We do this to avoid multiple shape names in Maya (eg. lots of pSphereShape1's or multiple Houdini Merge listings ; Alembic will take whatever the penultimate node to your ROP-alembic is called!)

In a primitive wrangle, this bit of code will create two text entry boxes, so you can input a group name and a shape name. If you were to call the group "squareGrp" and the name "square", then the resultant hierarchy would be "squareGrp/square/squareShape" in Maya.


string group = chs("MayaGroup");
string name = chs("Name");

group += chs("groupSuffix");
name += chs("geoSuffix");

s@path = group + '/' + name + '/' + name + 'Shape';


Remember to tick the "build hierarchy" box in the ROP-Alembic node & also to tick "use path".

voronoi fracture woes & exporting alembics to maya

Voronoi fracturing is often used to create destruction fx. It also creates a lot of dirty geometry, which leads to pain when exporting your geometry to Maya -

"UVs aren't per-vertex or per-polygon per-vertex, skipping"

 This also plays havok with motion blur and any other vertex attributes you might have in play.

Using a For-Each loop, or For-Each subnetwork (if using the subnetwork, attach a Connectivity SOP first, with a "class" attribute, so the For-Each knows what pieces to run over. You type "class" into the Attriubute field of the ForEach Subnetwork parameter box) use Clean SOPs to fix any nasty geo that might have been generated. You'll want to tick most of the boxes - your mileage may vary with the Non-Manifold option.

This probably won't fix the problem still - the fracturing process can make a lot of stray edges - 2 point primitives, which don't play nice.

drop down a Primitive Wrangle and use this code-
i@vertnum = primvertexcount(0,@primnum);

It creates a variable called vertnum that counts how many vertices you have in each primitive.

Follow this wrangle with a blast that has
@vertnum==2
in it's Group box. This will kill any stray edges & hopefully fixes everything!