给个英文的.个人理解可能会有点出入.基本上是这个意思. n
^T_pqV?X n9zS'VU A candela plot is a plot of luminous intensity, or flux per solid angle. In photometric !(!BW9Zt+ units, a luminous intensity plot is in units of candelas (lumens per steradian). In aBM'ROQ radiometric units, an intensity plot is in units of watts per steradian. Candela plots ax0:v!,e are commonly used in the design of illumination systems, especially those used in N_vVEIO9 the far field. |wf:|% Candela data can be collected from ray sets of Missed rays, rays Exiting a surface !U"1ZsO)l or rays Incident on a surface. Missed rays are a collection of all rays that “leave” E(T6s^8 the model and “go off to infinity.” Exiting rays are the collection of ray segments '_n{+eR74 following the intersection point of a ray at a surface. Due to ray splitting, several ];P^q`n=. ray segments may contribute to the candela data for each incident ray. Incident Av*R(d=` rays are the collection of ray segments which intersect the selected surface. No ? OBe!NDf surface selection is required for Missed rays but one is necessary for Exiting and S.+)">buH Incident rays. S,5>g07-` The candela plots represent flux versus angle and can be smoothed using the xG_ ;F Candela Options dialog box. The iso-candela plots can be presented as false _%s _w) color maps or contour plots. The distribution plots are graphs of cross-sectional `4cs.ab curves through the candela distribution. #K7i<Bf The orientation of the candela plots is determined by the Normal Vector and the O.=~/!( Up Vector, as specified in the Analysis|Candela Options dialog box. The k@5,6s:
normal vector specifies the axis of the candela plot and the up vector specifies [;VNuF “which way is up.”