if i have a curve (act as a path) then i want to copy/duplicate an object (ex : torus) along the path, but i want each of this copy will have its own orientation following the shape of the curve. what OP should i use?

kind like copy OP, but i want the orientation follow the path/curve and i want to control the number of copy- that will be distrubuted along the path.

clay~

As far as I know this isn't as straightforward as it may seem. Here http://www.odysseus.anderson.name/mikela/Houdini/RotateToNormal.hipnc [odysseus.anderson.name] is my solution. Basically I take the curve and resample it so I can get a good approximation of the tangent to the curve by comparing the position of adjacent points. I do this by giving a Point SOP two inputs–the resampled curve, and the resampled curve resorted with a -1 offset using the Sort SOP. In the point SOP I add normals $TX2-$TX, etc, and then with the Copy SOP I make sure “Rotate to Normal” is checked.

This technique leaves something to be desired. The uv's are messed up and the surface isn't smooth. I don't know exacly what you're looking for but you might have better results with the Skin SOP and a 2D cross-section.

Mike

instead of the “copy_sop” you can use “sweep_sop” :
use the “cross section” input for the geometrie , “backbone” for the curve.
the orientation of the copies should be ok.

yes i used sweep before, but the problem : i cannot control the number of copy ,it's controlled by the number of cv of the path, so i have to change the number of cv everytime i want to add a copy and it's hard to distributed the cv manually accross the path/curve to get the same distance from each other.

clay~

it's hard to distributed the cv manually accross the path/curve to get the same distance from each other.

just use the resample sop to add more points and distribute evenly…

deecue
just use the resample sop to add more points and distribute evenly…

this is cool, thanx a lot.

mikela
As far as I know this isn't as straightforward as it may seem. Here http://www.odysseus.anderson.name/mikela/Houdini/RotateToNormal.hipnc [odysseus.anderson.name] is my solution.

sorry, i tried to open this file , but i got a fatal error msg : segmentation fault.
probably different version? i use apprentice 6.1 fyi.

clay~