Calculate the angle between two planes

TDK_Long — Thu, 26 Jun 2025 04:13:57 GMT

Hi folks,

I have 30 discrete points in X, Y, Z defining plane 1, and 30 other points in X, Y, Z defining plane 2, I need to calculate the angle between plane 1 and plane 2. The ChatGPT provides the following JSL script, but it stuck at row #33. Could any of you help check the two attachments (*.jmp and *.jsl) to get this script going? Thanks a lot.

// Use current data table
dt = Current Data Table();
 
// Subset for Plane1 and Plane2
dt1 = dt << Subset( Where( :Plane == "Plane1" ), Output Table Name( "Plane1" ) );
dt2 = dt << Subset( Where( :Plane == "Plane2" ), Output Table Name( "Plane2" ) );
 
// Fit plane 1: z = a1*x + b1*y + c1
b1 = dt1 << Fit Model(
Y( :Z ),
Effects( :X, :Y ),
Personality( "Standard Least Squares" ),
Emphasis( "Effect Leverage" ),
Run( "Fit Model" )
);
coeff1 = b1 << Get Estimates;
a1 = coeff1["X"];
b1_ = coeff1["Y"];
 
// Fit plane 2: z = a2*x + b2*y + c2
b2 = dt2 << Fit Model(
Y( :Z ),
Effects( :X, :Y ),
Personality( "Standard Least Squares" ),
Emphasis( "Effect Leverage" ),
Run( "Fit Model" )
);
coeff2 = b2 << Get Estimates;
a2 = coeff2["X"];
b2_ = coeff2["Y"];
 
// Normal vectors: [a, b, -1]
n1 = [a1, b1_, -1];
n2 = [a2, b2_, -1];
 
// Compute dot product and magnitudes
dotProd = Sum( n1 * n2 );
mag1 = Sqrt( Sum( n1 ^ 2 ) );
mag2 = Sqrt( Sum( n2 ^ 2 ) );
 
// Compute angle in degrees
cosTheta = dotProd / (mag1 * mag2);
thetaRad = ACos( cosTheta );
thetaDeg = thetaRad * (180 / Pi());
 
// Display result
New Window( "Angle Between Planes",
Text Box( "Angle (degrees): " || Char( thetaDeg ) )
);

Re: Calculate the angle between two planes

Craige_Hales — Thu, 26 Jun 2025 00:30:06 GMT

No idea about the rest of the script, but line 33 isn't written in JSL.

n1 = [a1, b1_, -1];
n2 = [a2, b2_, -1];

Probably should be more like

n1 = a1 ||  b1_ || -1;
 or perhaps
n2 = a2 |/ b2_ |/ -1;

the n1 example should make a row vector and the n2 make a col vector.

Re: Calculate the angle between two planes

Craige_Hales — Thu, 26 Jun 2025 00:37:44 GMT

And the dot product is probably wrong too, you should look it up and figure out if JMP's element-wise multiply is what you need; the * is a matrix multiply which might not be the operator you need.

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Calculate the angle between two planes

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