HDK (12.5) add a tetrahedron within a SOP node???

[stkeg]

using houdini 12.5

i'm trying to add a tetrahedron (the one that comes as an example with the HDK and is created when compiling tetra.c in the tetprim directory of the toolkit samples)

trying to go through the examples of the sample code and docs on how to add geometry, but i'm not sure if i'm doing it right specifically for the tetrahedron.

i've tried adding things like this to the cookMySop function of the SOP node.

HDK_Sample::GU_PrimTetra *newtetra = static_cast<HDK_Sample::GU_PrimTetra *>(gdp->appendPrimitive(HDK_Sample::GU_PrimTetra::theTypeId()));

although it compiles, the sop doesn't show up in houdini. it does when i remove this bit of code. (houdini crashes)

GEO_PrimTetra *newtetra = static_cast<GEO_PrimTetra *>(gdp->appendPrimitive( GEO_PRIMTETRAHEDRON ));

it compiles and i can see the sop, but i can't add points or vertices to this tetra.

i've done a test where i simple add a geo_primpoly and can add vertices/points to the primitive and i can see it in houdini, but i haven't been successful with tetras.

what is the correct way of adding the tetrahedron?