Instancer Orientation With Poly Object

[combustible]

Hi, I'm trying to constrain - on a per particle basis - my particle instances to the normal of the polygonal object it is orbiting around. Basically I'm trying to get as close as possible to a normal constraint on a per-particle basis.

Say I have these arrows and I'm trying to make them orbit around a moderately complex polygonal object where their Up Axis is always facing in the Normal vector on the polygonal mesh at the nearest point.

I've tried using a custom attribute and the nearestPointOnMesh node, but there is little to no documentation on it so I'm not sure if I was using it correctly. It looked like it was only using one particle as the input position, though. And I'm not sure if there are more commands with nearestPointOnMesh or not.

Any help would be greatly appreciated.

[gwelch]

For Maya 7 up, select the particle and make your complex poly object a goal of the particle. Now open the particle "Goal weights and Objects" section, click the "Create goalWorldNormal" button. For a test object, create a nurbs cone, then Rotate Z negative 90 degerees and freeze transformation. Instance the cone to your particle. In the particle attribute editor, set the Instancer/Rotation Options/Aim Direction: to goalWorldNormalOPP" in the drop down list. Rewind and play. Adjust goal weights.

[combustible]

Thanks for the quick response, but I can't seem to get the desired result with this method. With a goal weight of near 1 I can get the particles to snap to the goal's vertices with the proper orientation, of course, and it's probably just that I don't know enough about goals. If it's not too much trouble could you go into a bit more detail? is there a way to get the normal of the goal without changing the position or is that against the nature of goals.

Also, when using the AimDirection attribute I Can't set the arrows to face in the direction of their velocity, which is another thing I'd like to have. I just want to constrain the up axis of each instance to the nearest normal of the poly object... I'm not sure that's possible but it would be great if it was!