In order to really solve this accurately I would NOT recommend using the PlaneNormal component. Not that it doesn't do a good job, but the organization of the resulting X and Y vectors of the plane will change depending on the quadrant of the generating vector. The better option IMHO is to take the construction of the plane into your own hands by using a series of vector operations to generate them...this will lead to a dependable structure that won't change on you.
To do this there are a number of steps. First you need to determine what your "control vector" will be. This control vector will be what stabilizes the plane system so they remain consistent. In my example I'm using the Z vector. Next you'll need to need to take the cross product of the Normal vector and your Control vector. This will become your X vector. Make sure to set the Unitize boolean on the cross product component to true (we want all those vectors to be 1). Next we want to take the cross product of our Normal vector and the previous cross product. This will generate our Y vector. Lastly we reassemble the plane from our origin point and the X and Y vectors that were created. Now we should have a very stable and predictable plane that doesn't reorient itself. http://grasshopper3d.googlegroups.com/web/PlaneFromNormal_Explicit.ghx?hl=en&gsc=jtKipSEAAACvEyeUZ_tOkfc8CH2TClpupaBUfXb6kfwKy5pFuU2DAUzfKN-m9S9niuHrq-IEXAE Note: This result will fail if the normal vector and the comparison are either parallel or antiparallel. Best, Damien On Feb 19, 3:03 pm, nitsirk <[email protected]> wrote: > Do you think there's a way I can [Rotate Plane] around the Z axis, > using an "absolute" expression in the expression editor? > > On Feb 19, 2:18 pm, David Rutten <[email protected]> wrote: > > > Hi nitsirk, > > > this is a tricky problem in 3D. There is a component which aligns > > planes, but it will adjust all the planes, not just the ones that you > > see as flipped. > > Then there's also the [Rotate Plan ]component which rotates a single > > plane around the z-axis and the [Align Plane] which only operates on a > > single plane. > > > -- > > David Rutten > > [email protected] > > Robert McNeel & Associates > > > On Feb 19, 7:54 pm, nitsirk <[email protected]> wrote: > > > > I'm trying to produce a set of planes from a series of vector normals. > > > My problem is that the some of the planes are automatically rotating > > > themselves so that the iso curves for them are upside down. Is there a > > > way to always have something rotated in a positive position?
