Look-At Rotation Questions..

[galagast]

In the attached file, (sample A) I used a common method of creating a matrix by using Cross Products and an Up vector to orient a set of points towards a direction. Which works great.

I'm just wondering, after stumbling upon the Look At VOP (sample B), it seems to pretty much do the same if I:

• Set the From parameter to the normalized direction that I want.
• Set the To parameter to {0,0,0}
• Leave the Up Input blank (probably defaults to {0,1,0} internally?).

I'm particularly curious about setting the To parameter to {0,0,0}. I would have thought that the parameter would always need a normalized vector.

The help card says:

Quote

This operator computes a 3×3 rotation matrix to orient the z-axis along the vector (to - from) under the transformation. If an up vector is specified, it will determine the roll.

 

My questions:

1. In the help card, does the (to - from) refer to (to minus from)?
2. Does this essentially mean that the Look At VOP can be used as a Vector to Matrix conversion tool for rotations?
3. Is there a VOP equivalent of the dihedral VEX function?
4. Are there any other methods we could use to do the same effect? Particularly, samples using quaternions would be great.

H15.5.607 Indie

look_at_v01.hiplc