Yes, we do !





The maths behind the CPC objects are described in the Help File. Retrieving the output diameter implies solving a quadratic equation with the CPC parameters.











This sort of tasks is usually addressed through user defined operands that are written with the Zemax Programming Language (ZPL). As described in this knowledge base article.





I’m attaching the ZPL Macro to this thread, and I’ve also copied it here for your reference.

 # Constants


PI = 3.14159265359


# CPC object number from Hx cell of ZPLM


cpc_number = PVHX()


# === Retrieve CPC parameters === #


# Radial aperture


aper = NPAR(1, cpc_number, 1)


# Angle (deg)


t = NPAR(1, cpc_number, 2)


# Angle (rad)


t = t/180*PI


# Volume index


is_vol = NPAR(1, cpc_number, 6)


nd     = NPAR(1, cpc_number, 7)


# Refracted angle (rad)


IF (nd > 1)


    IF (is_vol > 0)


        t = ASIN(SINE(t)/nd)


    ENDIF


ENDIF


# Length


L = NPAR(1, cpc_number, 3)


# =============================== #


# === Definitions from CPC Help file === #


C = COSI(t)


S = SINE(t)


P = 1+S


Q = 1+P


T = 1+Q


# ====================================== #


# Maximum length of the CPC


L_max = aper*(1+S)*C/(S*S)


# If current length is longer than maximum length


# change it to the maximum length


IF (L > L_max) THEN (L = L_max)


# Resolution of the quadratic equation for the 


# output radius


A_coeff = C*C


B_coeff = 2*(C*S*L+aper*P*P)


C_coeff = (L*L*S*S-2*aper*C*Q*L-aper*aper*P*T)


delta = SQRT(B_coeff*B_coeff-4*A_coeff*C_coeff)


# Physically meaningful solution


Output_radius = (-B_coeff+delta)/(2*A_coeff)


# Return to Merit Function


OPTRETURN 0, Output_radius 

This macro should be placed in the \Documents\Zemax\Macros folder, and can be called in the Merit Function through the ZPLM operand where Mac# is 2, and Hx corresponds to the CPC Object number in the non-sequential component editor.





The result looks as follow for a default CPC:








This operand can then be constrained with the OPGT and OPLT operands.

Please download the macro from the attachment below, the above macro is not the latest version!

When I try to use the macro, I get the error: Divide by zero error on line 42. Do you have any insight as to why/how I can remedy this?

Thanks!