vertexindex and vertexpoint

[abanoub]

Hi,,,

I'm facing some troubles understanding some vex functions , many HIP files include wrangles like

int vt0 = vertexindex(0,@primnum,0);
int vt1 = vertexindex(0,@primnum,1);

int pt0 = vertexpoint(0,vt0);
int pt1 = vertexpoint(0,vt1);

and I don't understand what the two functions return exactly ?

[konstantin magnus]

vertexindex returns a unique number for every vertex on your mesh. while vertexpoint tells you what point is connected to your vertex.

 

vertexindex.hipnc

[acey195]

pointvertex() will also give you the (usually first) vertex connected to a point (returns -1 if it is an isolated point). you could then use vertexnext() and vertexprev() to get more vertices connected to the same point.

pointvertices() will give you an int array of all the vertices connected to a point.

I generally always have this open when writing vex: https://www.sidefx.com/docs/houdini15.0/vex/functions/

the simple way to remember how these guys work, is the [first part of the name is the input] [second part of the name is the output]

[abanoub]

Thankx Konstantin

[abanoub]

Thankx Twan  , but sometimes docs don't give a good explanation of vex functions .

[konstantin magnus]

Youre totally right abanoub. The help documents should explain contexts more often.

A good way to find out what functions are doing is testing them in a simple, self-made scene, though. Just check how the attributes change in your geometry spreadsheet.