How do you get a rectangular light rotation

Rhino Developer
1

Hi

I am trying to create a PlaneSurface from a rectangular light. I can get the light position and direction, but how do you get the rotation pls? Rhinocommon.

Thanks

2

I think something like the following will work:

import rhinoscriptsyntax as rs
import scriptcontext as sc
import Rhino

def GetRectLightCorners(light):
    oPt=light.Geometry.Location
    len=light.Geometry.Length
    wid=light.Geometry.Width
    return [oPt,oPt+len,oPt+len+wid,oPt+wid]

def TestGetLightCornersFunction():
    lightID=rs.GetObject("Get light",256,True)
    lightObj=sc.doc.Objects.Find(lightID)
    corners=GetRectLightCorners(lightObj)
    print corners
    
TestGetLightCornersFunction()

(from the corners you can get the plane surface, of course)
–Mitch

3

Here is a way to get the plane surface directly… I haven’t yet figured out how to properly orient the surface normal to the light direction vector though (if that’s important to you)… --Mitch

import rhinoscriptsyntax as rs
import scriptcontext as sc
import Rhino

def GetRectLightPlaneSrf(light):
    oPt=light.Geometry.Location
    len=light.Geometry.Length
    wid=light.Geometry.Width
    plane=Rhino.Geometry.Plane(oPt,len,wid)
    u_interval = Rhino.Geometry.Interval(0, len.Length)
    v_interval = Rhino.Geometry.Interval(0, wid.Length)
    return Rhino.Geometry.PlaneSurface(plane, u_interval, v_interval)

def TestGetRectLightPlaneSrfFunction():
    lightID=rs.GetObject("Get light",256,True)
    if not rs.IsRectangularLight(lightID): return
    lightObj=sc.doc.Objects.Find(lightID)
    srf=GetRectLightPlaneSrf(lightObj)
    sc.doc.Objects.AddSurface(srf)
    sc.doc.Views.Redraw()
    
TestGetRectLightPlaneSrfFunction()
4

And finally… the plane surface normal will face in the direction of the light…

import rhinoscriptsyntax as rs
import scriptcontext as sc
import Rhino

def GetRectLightPlaneSrf(light):
    oPt=light.Geometry.Location
    len=light.Geometry.Length
    wid=light.Geometry.Width
    dir=light.Geometry.Direction
    plane=Rhino.Geometry.Plane(oPt,len,wid)
    u_interval = Rhino.Geometry.Interval(0, len.Length)
    v_interval = Rhino.Geometry.Interval(0, wid.Length)
    ang=Rhino.Geometry.Vector3d.VectorAngle(dir,plane.Normal)
    if ang < sc.doc.ModelAngleToleranceDegrees:
        return Rhino.Geometry.PlaneSurface(plane, u_interval, v_interval)
    else:
        plane.Flip()
        return Rhino.Geometry.PlaneSurface(plane, v_interval, u_interval)
    return planeSrf

def TestGetRectLightPlaneSrfFunction():
    lightID=rs.GetObject("Get light",256,True)
    if not rs.IsRectangularLight(lightID): return
    lightObj=sc.doc.Objects.Find(lightID)
    srf=GetRectLightPlaneSrf(lightObj)
    sc.doc.Objects.AddSurface(srf)
    sc.doc.Views.Redraw()
    
TestGetRectLightPlaneSrfFunction()
5

This works perfectly. Thank you,