Difference between revisions of "Physicsless part"

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(massless -> physicsless, since 1.0.2 the part mass is added to the parent; and medium/heavy landing gear are not physicsless (it's commented out in the cfg))
(Correction of internal contradiction. Update of version to reflect the added flags in the part list.)
 
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{{Move|Physicsless part|As of KSP 1.0.2, physicsless parts add their nominal mass to their parent part, so they are no longer massless as implied by the page title}}
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[[File:RV-105 RCS Thruster Block Delta V test.png|thumb|Delta-V comparison of three [[RV-105 RCS Thruster Block]] as massless and normal parts, before the changes introduced in [[1.0.1]]]]
[[File:RV-105 RCS Thruster Block Delta V test.png|thumb|Delta-V comparison of three [[RV-105 RCS Thruster Block]] as massless and normal parts]]
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'''Physicsless parts''' are parts where the physics don't work in the usual way. The mass of the part and the drag experienced by it are added to the parent's part. The part itself has no mass nor drag at its point of placement, but it still contributes to the vehicle's total mass and drag; in short, during movement, the added physicless parts would not generate mass-shift and drag that affects lateral stability. Before [[1.0.1]] the mass and the drag weren't added to the parent but just ignored. It is influenced by the <code>PhysicsSignificance</code> flag in the part configuration which must be set to 1 to make it physicsless.
Some parts within the game are listed as having a small mass, but in the config file a flag is set "PhysicsSignificance = 1". This has the effect that in flight physics calculations such as mass and drag are not calculated for that part. However, as of KSP 1.0.2, the part mass is instead added to the parent part, so that the vessel mass is increased appropriately even if the part itself is ignored for the physics simulation.
 
  
 
When constructing a craft, the [[root part]] can't be such a part.
 
When constructing a craft, the [[root part]] can't be such a part.
  
 
== Behaviour ==
 
== Behaviour ==
A craft with only physicsless parts starts to oscillate after a short time and then starts to destroy itself. But this is usually not possible because the root part is always not a physicsless part. The game can change the property on the fly, because when a new root part after decoupling would be physicsless the game removes that special status.
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A craft with only physicsless parts starts to oscillate after a short time and then starts to destroy itself. But this is usually not possible because the root part is always not a physicsless part. The game can change the property on the fly, so that when a new root part after decoupling would be physicsless the game removes that special status.
  
 
== List of physicsless parts ==
 
== List of physicsless parts ==
''Parts with PhysicsSignificance = 1 as of 1.0.2''
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Physicsless parts as of 1.10.1:
  
* [[2HOT Thermometer]]
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{{:Physicsless part/List}}
* [[Atmospheric Fluid Spectro-Variometer]]
 
* [[BZ-52 Radial Attachment Point]]
 
* [[Communotron 16]]
 
* [[Communotron 88-88]]
 
* [[Cubic Octagonal Strut]]
 
* [[Double-C Seismic Accelerometer]]
 
* [[EAS-4 Strut Connector]]
 
* [[FL-A5 Adapter]]
 
* [[FTX-2 External Fuel Duct]]
 
* [[GRAVMAX Negative Gravioli Detector]]
 
* [[Illuminator Mk1]] (spot)
 
* [[Illuminator Mk2]] (wide)
 
* [[LY-01 Fixed Landing Gear]]
 
* [[LY05 Steerable Landing Gear]]
 
* [[O-10 MonoPropellant Engine]]
 
* [[Octagonal Strut]]
 
* [[OX-STAT Photovoltaic Panels]]
 
* [[Pegasus I Mobility Enhancer]]
 
* [[Place-Anywhere 7 Linear RCS Port]]
 
* [[PresMat Barometer]]
 
* [[RV-105 RCS Thruster Block]]
 
* [[Small Hardpoint]]
 
* [[Telus-LV Bay Mobility Enhancer]]
 
* [[Telus Mobility Enhancer]]
 
* [[TR-38-D]] (Size 3 decoupler)
 
* [[Vernor Engine]]
 
* [[Z-100 Rechargeable Battery Pack]]
 
* [[Z-400 Rechargeable Battery]]
 
  
Note that several parts, such as the [[LT-2 Landing Strut]], have PhysicsSignificance = 0 in its part.cfg. This does nothing, and the part behaves as normal.
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Note that several parts, such as the [[LT-2 Landing Strut]], have <code>PhysicsSignificance = 0</code> in its part.cfg. This does nothing, and the part behaves as normal.
  
 
== See also ==
 
== See also ==

Latest revision as of 09:14, 6 January 2021

Delta-V comparison of three RV-105 RCS Thruster Block as massless and normal parts, before the changes introduced in 1.0.1

Physicsless parts are parts where the physics don't work in the usual way. The mass of the part and the drag experienced by it are added to the parent's part. The part itself has no mass nor drag at its point of placement, but it still contributes to the vehicle's total mass and drag; in short, during movement, the added physicless parts would not generate mass-shift and drag that affects lateral stability. Before 1.0.1 the mass and the drag weren't added to the parent but just ignored. It is influenced by the PhysicsSignificance flag in the part configuration which must be set to 1 to make it physicsless.

When constructing a craft, the root part can't be such a part.

Behaviour

A craft with only physicsless parts starts to oscillate after a short time and then starts to destroy itself. But this is usually not possible because the root part is always not a physicsless part. The game can change the property on the fly, so that when a new root part after decoupling would be physicsless the game removes that special status.

List of physicsless parts

Physicsless parts as of 1.10.1:

Note that several parts, such as the LT-2 Landing Strut, have PhysicsSignificance = 0 in its part.cfg. This does nothing, and the part behaves as normal.

See also