How can I calculate the PI of Alignment Spiral?

[handgth]

Hello everyone,

I'm working with C3D API to create and modify Civil objects by C# and I want to create Alignment with some curve, spiral.

I want to use this method: 

public AlignmentSpiral AddFixedSpiral(
	int previousEntityId,
	Point3d startPoint,
	Point3d spiralPI,
	Point3d endPoint,
	SpiralType definitionType
)

to create alignment spiral.

But I can not find the Spiral PI.

How can I calculate the PI of spiral when I have start point, end point, length and radius of this spiral?

Please help me.

Thank you.

[essam-salah]

@handgth 

have you tried using:

AddFixedSpiral(int previousEntityId, double startRadius, double endRadius, double length, SpiralType spiralDefinition)

instead, it doesn't ask for PI.

[essam-salah · Accepted solution]

@handgth 

PI is the intersection of the start/end tangents of the curve.

 

[handgth]

@essam-salah, Thank you.

I try to use the method 

AddFixedSpiral(int previousEntityId, double startRadius, double endRadius, double length, SpiralType spiralDefinition)

But the application throw the error.

Did I pass something wrong? 

[handgth]

public AlignmentSTS AddFreeSSBetweenCurves(
	int previousEntityId,
	int nextEntityId,
	double spRatio,
	SpiralParamType spType,
	SpiralType spiralDefinition
)

spRatioType: System.Double
Specifies spiral1 and spiral2 ratio (length or A-value) .

How can I pass the parameter for "spRatio" ( A-value of spiral1 or spiral2)?

[essam-salah]

@handgth
if you able to post your code it would be helpful.

[essam-salah]

Did I pass something wrong? 

---

this error because you passed a station out of the alignment range, try to check any station you pass is lies between alignment start station and end station.

[essam-salah · Accepted solution]

---

spRatioType: System.Double
Specifies spiral1 and spiral2 ratio (length or A-value) .

How can I pass the parameter for "spRatio" ( A-value of spiral1 or spiral2)?

---

here is the >> Spiral Definitions << 

[handgth]

---

@essam-salah wrote:

Did I pass something wrong? 

---

this error because you passed a station out of the alignment range, try to check any station you pass is lies between alignment start station and end station.

this error because you passed a station out of the alignment range, try to check any station you pass is lies between alignment start station and end station.

---

In the method
AddFixedSpiral(int previousEntityId, double startRadius, double endRadius, double length, SpiralType spiralDefinition)
do not have station.

[handgth]

I want to create an alignment have 8 entities like this :

Line - Clothoid - Arc - Clothoid - Clothoid - Arc - Clothoid - Line.

[handgth]

I solved my problem by using combination method to create Spiral and method to create STS.

Thanks everyone for the support.