# How to creates a serie of iso-clips in CFDpost in order to cut a surface by equal angular sectors?

 Assumption:1-The axis is Z axis.2- Each angular sectors have the same size.Note:Theta function uses atan2(x,y) function.Due to smoothing of atan2(x,y) function discontinuity (-180°/+180°) , the created surface with iso-clip may include a very small surface in the area close to the discontinuity (close to +180° of angle Theta). For example, if you want to clip your surface between 0 and 45° you may have include a small part that comes from the smoothing between -180 and + 180°.An additional test on postive X or postive Y is added to avoid this artifact in the script.How to run it?:In CFD post read the following PERL script via Session-->Play Session.SCRIPT:#enter name of the surface to split with angles.!\$name="FLOW_OUTFLOW";# enter the number of angular sectors.!\$numsteps=7;LIBRARY: CEL: EXPRESSIONS: theta1 = atan2(y,x) theta2 = atan2(-x,y) END ENDENDUSER SCALAR VARIABLE: Theta 1 Boundary Values = Conservative Calculate Global Range = Off Expression = theta1 Recipe = ExpressionENDUSER SCALAR VARIABLE: Theta 2 Boundary Values = Conservative Calculate Global Range = Off Expression = theta2 Recipe = ExpressionEND! for (\$i=0;\$i<\$numsteps;\$i++)!{!\$dangle=360/\$numsteps;!\$num0=\$i*\$dangle;!\$num1=(\$i+1)*\$dangle;! if (\$num1<180.0)!{ISO CLIP: Iso Clip \$i Location List = \$name ISO CLIP LIMITER: Iso Clip Limiter 1 Limiter Operation = Greater Or Equal To Value = \$num0 [degree]-90 [degree] Variable = Theta 2 Variable Boundary Values = Conservative END ISO CLIP LIMITER: Iso Clip Limiter 2 Limiter Operation = Less Or Equal To Value = \$num1 [degree]-90 [degree] Variable = Theta 2 Variable Boundary Values = Conservative END ISO CLIP LIMITER: Iso Clip Limiter 3 Limiter Operation = Greater Or Equal To Value = 0 [m] Variable = Y Variable Boundary Values = Hybrid ENDEND! }! else!{!if (\$num0<180.0)! {ISO CLIP: Iso Clip \$i Location List = \$name ISO CLIP LIMITER: Iso Clip Limiter 1 Limiter Operation = Greater Or Equal To Value = \$num0 [degree]-90 [degree] Variable = Theta 2 Variable Boundary Values = Conservative END ISO CLIP LIMITER: Iso Clip Limiter 2 Limiter Operation = Less Or Equal To Value = \$num1 [degree]-90 [degree] Variable = Theta 2 Variable Boundary Values = Conservative END ISO CLIP LIMITER: Iso Clip Limiter 3 Limiter Operation = Less Or Equal To Value = 0 [m] Variable = X Variable Boundary Values = Hybrid ENDEND!} else!{ISO CLIP: Iso Clip \$i Location List = \$name ISO CLIP LIMITER: Iso Clip Limiter 1 Limiter Operation = Greater Or Equal To Value = \$num0 [degree]-360 [degree] Variable = Theta 1 Variable Boundary Values = Conservative END ISO CLIP LIMITER: Iso Clip Limiter 2 Limiter Operation = Less Or Equal To Value = \$num1 [degree]-360 [degree] Variable = Theta 1 Variable Boundary Values = Conservative END ISO CLIP LIMITER: Iso Clip Limiter 3 Limiter Operation = Less Or Equal To Value = 0 [m] Variable = Y Variable Boundary Values = Hybrid ENDEND!}!}!}