instance path

Say you have some points and you want to instance an object from disk to them..

in a point wrangle-

 s@instancepath=chs("path");

create the input box and type in the path of your object eg: c:\dave\ball.obj

beneath the point wrangle, add an instance node. ta da!

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".

Exporting simple multiple objects from Houdini to Maya

Assuming... you've duplicated objects around, animated them etc... AND the objects are single mesh things. Eg. a Sphere, a torus.... Not a multi-object thing.

Create a "connectivity" node and set the connectivity type to Primitive. This should be connected to the group of objects you're exporting.

This creates a Primitive attribute which assigns an integer value, based on the object's "shell".
eg. the primitives in Cube 1 might have a value of 0, Cube3 might have a value of 4 or whatever..

Connect a Primitive Wrangle and put in:

s@path = 'fish_GRP/fish_' + itoa(i@class) + '_GEO/fish_'+ itoa(i@class)+'_GEOShape';

where the path attribute created is making a group called "fish_GRP" and objects called "fish_1_GEO" and their respective Maya shape nodes called "fish_1_GEOShape".

It seems necessary to build the complete hierarchy for Maya, otherwise the individual shape nodes are not so easily accessible..

Finally, using a ROP_Alembic node, output your file, making sure that you have
"Build Hierarchy from Attribute" ticked ON, and set to "path".
The other bits are left as default...