gopherCG

12-23-2003, 04:51 PM

Hi,

I'm trying to create a helper object (dummy or point) on each vertex of a spline, and have the helper object rotate so it follows the tangent of the spline.

I've tried these three ways so far (ptTangent receives a point3 vector; n*fraction was used in a loop to run through all vertices in a selected spline):

1. ptTangent = tangentCurve3D $ 1 (n*fraction)

2. ptTangent = pathTangent $ 1 (n*fraction)

3. ptTangent = normalize ((getOutVec $ 1 n) - (getInVec $ 1 n))

Then I wrote a rectilinear-to-polar coordinate conversion function to find the helper's rotation using the vector, but it only works on the 2D plane since my math is now high school level.

Well, 1. and 2. gave strange results, while 3. was accurate (on 2D plane only).

Mind if you tell me how to use the functions in 1. and 2., or you have an easier alternative?

using Max 4

I'm trying to create a helper object (dummy or point) on each vertex of a spline, and have the helper object rotate so it follows the tangent of the spline.

I've tried these three ways so far (ptTangent receives a point3 vector; n*fraction was used in a loop to run through all vertices in a selected spline):

1. ptTangent = tangentCurve3D $ 1 (n*fraction)

2. ptTangent = pathTangent $ 1 (n*fraction)

3. ptTangent = normalize ((getOutVec $ 1 n) - (getInVec $ 1 n))

Then I wrote a rectilinear-to-polar coordinate conversion function to find the helper's rotation using the vector, but it only works on the 2D plane since my math is now high school level.

Well, 1. and 2. gave strange results, while 3. was accurate (on 2D plane only).

Mind if you tell me how to use the functions in 1. and 2., or you have an easier alternative?

using Max 4