Physicsless part

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Revision as of 08:18, 3 May 2015 by Jdrexler (talk | contribs) (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))
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Delta-V comparison of three RV-105 RCS Thruster Block as massless and normal parts

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.


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.

List of physicsless parts

Parts with PhysicsSignificance = 1 as of 1.0.2

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