Greg M. Johnson <gregj:-)565### [at] aolcom> wrote:
> I'm making a mesh2 version of a sphere sweep.  At multiple segments along
> the cubic spline, I'm building a mesh2 at a given radius from the spline and
> normal to its tangent.   In this case (think a simple cylinder),  would the
> normals be equivalent to the vertex points themselves?

  Normal vectors should always be perpendicular to the surface the mesh
is approximating.
  In your case, when you are approximating a sphere sweep with a mesh,
the vertex points should be located where the surface of the sphere
sweep would be (if it was there), and the normal vector at a certain
vertex point should be perpendicular to the surface of the sphere sweep
at that point, pointing outwards.

  That is, if you created a cylinder for each vertex point so that one
end of the cylinder is at the vertex point and the other end of the cylinder
is at the vertex point + the normal vector, you would get "spikes" on the
surface of the sphere sweep, which are perpendicular to this surface.

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

Post a reply to this message