If you only have a N (normal) vector, copy to points SOP will auto calculate up vector to get a orient. The up vector and final orient may not meet your requirement.
There are many ways to correct the orient:
try to set v@up = {0, 1, 0}
try the orientation along curve SOP in Houdini 18 to create orient but not use poly frame SOP
try the copy to curves SOP in Houdini 18
try my HDA : Point Orient [vimeo.com] to get orient (or qLib :: orient, also can see in my link)
The Official Doc [www.sidefx.com] says : Up vector of the copy (+Y axis of the copy, if no orient)… But it doesn't seem to be the case here.
It works perfectly and instantly ! Thanks again. Here's the final result in case newbies like me are interested (the HIP is zipped with the texture file)
