derrick

See: GU_RayIntersect::minimumPoint()

https://www.sidefx.com/docs/hdk/class_g_u___ray_intersect.html [www.sidefx.com]

PaoloGiandoso
When you say channel, do you mean a Keyframe? Is it the same thing?
Does creating a keyframe tells houdini to evaluate the text as an expression instead of a string?

Yes, that is what I mean. Once you set a keyframe, you can click on the parameter's label to switch between viewing the expression and what it evaluates to. I find this more useful than using backticks because the colour makes it easier to notice there is an expression and I can click on the label to see what value the expression produced.

PaoloGiandoso
Question
I wrote
`details(-1,"cutPoint")`
with backticks instead of
details(-1,"cutPoint")
why was that a mistake? Is not the attribute an expression?

I don't see any mistake there. You should be able to use backticks around the expression. I generally prefer creating a channel and writing an expression without the backticks because I find the change in colour makes it easier for me to easy notice what fields have expressions.

PaoloGiandoso
I saw that toward the end you used the function vertexprimindex(0, hedge_srcvertex(0, hEdgeToCut))
Is the primitive Vertex Index the half-edge number requested by the polySplit SOP?

The format expected by PolySplit doesn't use half-edge numbers. Imagine enumerating the edges of a polygon. It expects that number for your edge in the polygon. This is really the same number as if you enumerated the vertices in the polygon.