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Don't include shoulders in CG calculation for applying parallel axis theorem to longitudinal inertia, as they aren't included in calculation of longitudinal inertia itself.

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This commit is contained in:
JoePfeiffer 2023-10-15 06:20:10 -06:00
parent 1f55a0b27c
commit bcdf32ecba
1 changed files with 15 additions and 4 deletions
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19
core/src/net/sf/openrocket/rocketcomponent/SymmetricComponent.java
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@ -281,14 +281,25 @@ public abstract class SymmetricComponent extends BodyComponent implements BoxBou
/** /**
* Calculate CG of the component by integrating over the length of the component. * Return the CG and mass of the component. Subclasses may
* The method caches the result, so subsequent calls are instant. Subclasses may
* override this method for simple shapes and use this method as necessary. * override this method for simple shapes and use this method as necessary.
* *
* @return The CG+mass of the component. * @return The CG+mass of the component.
*/ */
@Override @Override
public Coordinate getComponentCG() { public Coordinate getComponentCG() {
return getSymmetricComponentCG();
}
/**
* Calculate CG of the symmetric component by integrating over the length of the component.
* The method caches the result, so subsequent calls are instant. We need this method because subclasses
* override getComponentCG() and include mass of shoulders
*
* @return The CG+mass of the component.
*/
private Coordinate getSymmetricComponentCG() {
if (cg == null) if (cg == null)
integrate(); integrate();
return cg; return cg;
@ -491,7 +502,7 @@ public abstract class SymmetricComponent extends BodyComponent implements BoxBou
longitudinalInertia /= vol; longitudinalInertia /= vol;
// Shift longitudinal inertia to CG // Shift longitudinal inertia to CG
longitudinalInertia = Math.max(longitudinalInertia - pow2(getComponentCG().x), 0); longitudinalInertia = longitudinalInertia - pow2(getSymmetricComponentCG().x);
} }
@ -548,7 +559,7 @@ public abstract class SymmetricComponent extends BodyComponent implements BoxBou
rotationalInertia /= surface; rotationalInertia /= surface;
// Shift longitudinal inertia to CG // Shift longitudinal inertia to CG
longitudinalInertia = Math.max(longitudinalInertia - pow2(getComponentCG().x), 0); longitudinalInertia = longitudinalInertia - pow2(getSymmetricComponentCG().x);
} }