Migrating expressions that include angular measures

Note:

If you are migrating expressions from a version of Simcenter 3D prior to 2019.2 and the formulas for the expressions contain products of angular and non-angular measures, this topic contains important information that you should read to avoid unexpected results. Otherwise, you can ignore this topic.

When you migrate an expression that contains the product of an angular and a non-angular measure from a version of Simcenter 3D prior to 2019.2, the software may not return the value that you expect because of the following changes that were made to the software in Simcenter 3D 2019.2:

• The base unit for angles changed from degrees to radians.

• For expressions that include products of angular and non-angular measures that are being migrated from a version of Simcenter 3D prior to 2019.2, the software automatically appends a correction factor to the formula for the expression. The software stores and evaluates the expression with the correction factor, and the correction factor appears in the formula for the expression when it is displayed in the Expressions dialog box.

The following examples demonstrate what happens when you migrate expressions from a version of Simcenter 3D prior to 2019.2 to the current version.

Migrating expressions whose formulas include angles in radians and correction factors

Suppose that you created the following expression where the angular measure is in radians in a version of Simcenter 3D prior to 2019.2:

25[mm]*3[radians]*PI()/180

When you open the model that contains this expression in the current version, the software stores and displays the following formula for the expression:

(25[mm]*3[radians]*PI()/180)*(180/PI())

where 180/PI() is the correction factor that the software appends to the formula for the expression.

In this example, the correction factor that the software appends to the expression corrects for the presence of the correction factor that you included in the formula for the expression when you created the expression. When coupled with the change of base units from degrees to radians, the net effect is that the software evaluates the automatically corrected formula for the expression to the following result:

25,{\rm{mm}},\left( {3,{\rm{radians}}} \right)\left( {\frac{\pi }{{180}}} \right)\left( {\frac{{180}}{\pi }} \right) = 75,{\rm{mm}}

where the first quotient is the correction factor that you included in the formula for the expression, and the second quotient is the correction factor that the software applies automatically.

Migrating expressions whose formulas include angles in radians but without correction factors

Suppose that you created the following expression where the angular measure is in radians in a version of Simcenter 3D prior to 2019.2:

25[mm]*3[radians]

When you open the model that contains this expression in the current version, the software stores and displays the following formula for the expression:

(25[mm]*3[radians])*(180/PI())

where 180/PI() is the correction factor that the software appends to the formula for the expression.

In this example, the correction factor that the software appends to the expression causes the software to yield the following result:

25,{\rm{mm}},\left( {3,{\rm{radians}}} \right)\left( {\frac{{180}}{\pi }} \right) = 4297.1....,{\rm{mm}}

where the quotient is the correction factor that the software applies automatically.

Migrating expressions whose formulas include angles in degrees and correction factors

Suppose that you created the following expression where the angular measure is in degrees in a version of Simcenter 3D prior to 2019.2:

25[mm]*3[degrees]*PI()/180

When you open the model that contains this expression in the current version, the software stores and displays the following formula for the expression:

(25[mm]*3[degrees]*PI()/180)*(180/PI())

where 180/PI() is the correction factor that the software appends to the formula for the expression.

In this example, the correction factor that the software appends to the expression corrects for the presence of the correction factor that you included in the formula for the expression when you created the expression. When coupled with the change of base units from degrees to radians, the net effect is that the software evaluates the automatically corrected formula for the expression to the following result:

25,{\rm{mm}}\left( {3,{\rm{degrees}}} \right)\left( {\frac{\pi }{{180}}} \right)\left( {\frac{\pi }{{180}}} \right)\left( {\frac{{180}}{\pi }} \right) = 1.3089....,{\rm{mm}}

where the first quotient is applied by the software to convert the angle to the base unit of radians, the second quotient is the correction factor that you included in the formula for the expression, and the third quotient is the correction factor that the software applies automatically.

Migrating expressions whose formulas include angles in degrees but without correction factors

Suppose that you created the following expression where the angular measure is in degrees in a version of Simcenter 3D prior to 2019.2:

25[mm]*3[degrees]

When you open the model that contains this expression in the current version, the software stores and displays the following formula for the expression:

(25[mm]*3[degrees])*(180/PI())

where 180/PI() is the correction factor that the software appends to the formula for the expression.

In this example, the correction factor that the software appends to the expression causes the software to yield the following result:

25,{\rm{mm}}\left( {3,{\rm{degrees}}} \right)\left( {\frac{\pi }{{180}}} \right)\left( {\frac{{180}}{\pi }} \right) = 75,{\rm{mm}}

Additional examples

The following table provides additional examples of the results that the software returns as a function of the version in which the expression was created:

Product	Expression dimensionality (units)	Formula for the expression (as entered by the user)	Version in which the expression was created	Value for the expression
rθ	Displacement (mm)	25[mm]*3[radians]	Pre-2019.2	4297.1....[mm]
Current	75[mm]
25[mm]*3[degrees]	Pre-2019.2	75[mm]
Current	1.3089....[mm]
25[mm]*3[radians]*PI()/180	Pre-2019.2	75[mm]
Current	1.3089....[mm]
25[mm]*3[degrees]*PI()/180	Pre-2019.2	1.3089....[mm]
Current	0.02284....[mm]
rω2	Acceleration (mm/sec^2)	25[mm]*(2[radians/sec]^2)	Pre-2019.2	328280.6....[mm/sec^2]
Current	100[mm/sec^2]
25[mm]*(2[degrees/sec]^2)	Pre-2019.2	100[mm/sec^2]
Current	0.03046....[mm/sec^2]
25[mm](2[radians/sec]^2)((PI()/180)^2)	Pre-2019.2	100[mm/sec^2]
Current	0.03046....[mm/sec^2]
25[mm](2[degrees/sec]^2)((PI()/180)^2)	Pre-2019.2	0.03046....[mm/sec^2]
Current	0.000009279....[mm/sec^2]

Using the automatic correction feature

As a best practice, use the automatic correction feature when you migrate expressions that were created in a version of Simcenter 3D prior to 2019.2 to the current version, and the expressions that you are migrating contain products of angular and non-angular measures and correction factors.

When you migrate expressions that were created in a version of Simcenter 3D prior to 2019.2 to the current version, and the expressions that you are migrating contain products of angular and non-angular measures without correction factors, it is best to disable the automatic correction feature. To do so, specify the following environment variable: UGII_KF_DONT_CONVERT_FORMULAS_FOR_RADIAN_UNITS=TRUE

When you specify this environment variable, the software:

• Does not add correction factors to expressions migrated from a version of Simcenter 3D prior to 2019.2 that contain products of angular and non-angular measures.

• Processes expressions migrated from a version of Simcenter 3D prior to 2019.2 the same as expressions created in Simcenter 3D 2019.2 or later versions.

The following table provides examples of the results that the software returns as a function of the version in which the expression was created when you specify UGII_KF_DONT_CONVERT_FORMULAS_FOR_RADIAN_UNITS=TRUE.

Product	Expression dimensionality (units)	Formula for the expression (as entered by the user)	Version in which the expression was created	Value for the expression
rθ	Displacement (mm)	25[mm]*3[radians]	Pre-2019.2	75[mm]
Current	75[mm]
25[mm]*3[degrees]	Pre-2019.2	1.3089....[mm]
Current	1.3089....[mm]
25[mm]*3[radians]*PI()/180	Pre-2019.2	1.3089....[mm]
Current	1.3089....[mm]
25[mm]*3[degrees]*PI()/180	Pre-2019.2	0.02284....[mm]
Current	0.02284....[mm]
rω2	Acceleration (mm/sec^2)	25[mm]*(2[radians/sec]^2)	Pre-2019.2	100[mm/sec^2]
Current	100[mm/sec^2]
25[mm]*(2[degrees/sec]^2)	Pre-2019.2	0.03046....[mm/sec^2]
Current	0.03046....[mm/sec^2]
25[mm](2[radians/sec]^2)((PI()/180)^2)	Pre-2019.2	0.03046....[mm/sec^2]
Current	0.03046....[mm/sec^2]
25[mm](2[degrees/sec]^2)((PI()/180)^2)	Pre-2019.2	0.000009279....[mm/sec^2]
Current	0.000009279....[mm/sec^2]

Caution:

As a best practice, do not specify NX_USE_ANGULAR_UNITS_FOR_DISTANCE_CALCULATIONS as an environment variable when running Simcenter 3D 2019.2 or later.

Behavior of versions of Simcenter 3D prior to 2019.2

For information on how past versions of Simcenter 3D processed the products of angular and non-angular measures, see the following:

• For versions of Simcenter 3D prior to 11, see Processing of angular and non-angular measures in versions prior to Simcenter 3D 11.

• For Simcenter 3D 11 and Simcenter 3D 12, see Processing of angular and non-angular measures in Simcenter 3D versions 11 and 12.

• For Simcenter 3D 2019.1, see Processing of angular and non-angular measures in Simcenter 3D 2019.1.

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