Slightly modified version of THOMAS HOLLIER's Maya Camera Frustrum Visualizer

frustrum_visualizer.py

## Author: THOMAS HOLLIER
## Modified: Arda Kutlu
## http://relentlessplay.com/maya-frustum-visualizer/

import maya.cmds as cmds
import math, sys
 
#--------- Gather relevant camera attributes
import maya.cmds as cmds
import math, sys
 
#--------- Gather relevant camera attributes
camera = cmds.ls(selection=True)
 
if not cmds.objectType(camera, isType="camera"):
	print "ERROR: You need to select a camera."
	sys.exit(0)
 
focalLength = cmds.getAttr(camera[0]+".focalLength")
horizontalAperture = cmds.getAttr(camera[0]+".cameraAperture")[0][0]
verticalAperture = cmds.getAttr(camera[0]+".cameraAperture")[0][1]
nearClipping = cmds.getAttr(camera[0]+".nearClipPlane")
farClipping = cmds.getAttr(camera[0]+".farClipPlane")
 
print "---- Camera Attributes:\n\tfocal length: %s\n\thorizontal aperture: %s" % (focalLength, horizontalAperture)
 
#--------- compute FOV just for kicks, and to verify numbers match
adjacent = focalLength
opposite = horizontalAperture*.5*25.4
 
print "---- Right Triangle Values:\n\tadjacent: %s\n\topposite: %s" % (adjacent, opposite)
 
horizontalFOV = math.degrees(math.atan(opposite/adjacent))*2
 
print "\tcomputed horizontal FOV: %s" % (horizontalFOV)
 
#--------- calculate ratios
plane = horizontalAperture*25.4
nearScaleValue = nearClipping*plane/focalLength
farScaleValue = farClipping*plane/focalLength
 
print "---- Lens:\n\tprojection ratio: %s" % (plane/focalLength)
 
#--------- build geometry
myCube = cmds.polyCube(w=1, h=1, d=farClipping-nearClipping, sy=1, sx=1, sz=1, ax=[0,1,0], ch=1, name=camera[0].replace("Shape", "Frustrum"))
 
cmds.setAttr(myCube[0]+".translateZ", nearClipping+(farClipping-nearClipping)*.5)
cmds.makeIdentity(apply=True, t=1, r=1, s=1, n=0, pn=1);
cmds.setAttr(myCube[0]+".rotatePivotZ", 0)
cmds.setAttr(myCube[0]+".scalePivotZ", 0)
cmds.setAttr(myCube[0]+".rotateY", 180)
 
#--------- use expressions to update frustum geo as FOV and apertures are changed 
initial_farClip = cmds.getAttr("%s.farClipPlane" %camera[0])
scaleZ = "%s.farClipPlane / %s" % (camera[0], initial_farClip)
scaleX = "%s.scaleZ*%s*%s.horizontalFilmAperture*25.4/%s.focalLength" % (myCube[0],initial_farClip,camera[0],camera[0])
scaleY = "%s.scaleZ*%s*%s.verticalFilmAperture*25.4/%s.focalLength" % (myCube[0],initial_farClip,camera[0],camera[0])
 
cmds.move(0,0,0, myCube[0]+".f[2]", absolute=True)
cmds.scale(nearScaleValue, 0, 1, myCube[0]+".f[2]", pivot=[0,0,0])
cmds.expression(s="%s.scaleZ = %s;%s.scaleX = %s;%s.scaleY = %s;" % (myCube[0],scaleZ,myCube[0],scaleX,myCube[0],scaleY), n="%s_Expr" % myCube[0])
cmds.parent(myCube, camera, relative=True)