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A Kerbal Space Program plugin designed to implement switching of part meshes, resources, and nodes
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Latest commit 37331f2 Jun 9, 2019


A Kerbal Space Program plugin designed to implement switching of part meshes, resources, and nodes

This mod will not change anything by itself, but is designed to be used by other mods to enable part subtype switching

Forum Thread


  • KSP version 1.7.1 (build 2539) is the only supported KSP version
  • ModuleManager is required.


  • Remove any previous installation of B9PartSwitch
  • Make sure the latest version of ModuleManager is installed
  • Copy the B9PartSwitch directory to your KSP GameData directory


The source can be found at Github


This plugin is distributed under LGPL v3.0



  • Recompile against KSP 1.7.1
  • Fix part action window showing removed resources in KSP 1.7.1
  • Add Russian localization


  • Fix part into button being shown when there's no info to display
  • Provide more context for subtype initialization errors in the warning dialog


  • Compile for KSP 1.7.0
  • Remove ModuleB9PropagateCopyEvents from parts since KSP handles this correctly now
    • Leave empty class so that KSP doesn't complain when loading craft/vessels
  • All initialization errors now warn the user but allow the game to continue
  • Add fuzzy matching for attach node toggling
    • ? will match any one character, * will match anything (or nothing)
    • All matching nodes will be switched
  • Allow moving and rotation of transforms
    • Subtypes can now have TRANSFORM nodes
      • Each one should nave a name which is the name of the transform
      • Each one can have a positionOffset = x, y, z which is a local offset for that transform
        • Any number of modules can modify a transform's position (it's additive)
      • Each one can have a rotationOffset = x, y, z which is a local rotation offset
        • Only one module can modify a transform's position
  • Remove KSP localization debug logging
  • Add Brazilian Portuguese localization
  • Localize switch subtype button
  • Fix texture switches incorrectly saying the current texture wasn't found when really the new texture wasn't found
  • Use more correct part names in some log messages
  • Allow subtypes to specify a mirror symmetry counterpart
    • Subtypes now accept a mirrorSymmetrySubtype value which is the subtype name of the mirror symmetry subtype
    • When placing the part in mirror symmetry, the symmetry counterpart will use this mirror symmetry subtype, otherwise it will use the normal subtype


  • Recompile against KSP 1.6.1
  • Fix misspellings in fatal error and serious warning handlers


  • Moved stack nodes now respect scale, rescaleFactor, and TweakScale
  • Moved surface attach node now respects scale and rescaleFactor
  • When only one subtype is present, disable switching GUI and display subtype title as non-interactable string
  • Downgrade incompatible resource switching module to a warning and disable B9 resource switching in that case
  • French localization


  • Allow moving stack nodes
    • Within a SUBTYPE, NODE nodes take a name (node ID) and a position (x, y, z position of the node)
  • Fix log message for duplicated subtype names
  • Fix texture switching behaving weirdly when copying a part in the editor


  • Fix issues with resource switching and stock delta-v simulation code
    • Exception when copying a part in the editor
    • Delta-v simulation was probably off as well


  • Recompile against KSP 1.5.1
  • Downgrade certain fatal errors to warnings
    • The user will still get an on-screen message but it can be dismissed without closing the game
    • Duplicate subtype names is now only a serious warning
    • Subtype without a name is now only a serious warning


  • Fix .version file again again


  • Fix .version file again


  • Fix .version file still listing KSP 1.4.x


  • Recompile against KSP 1.5
  • Provide better context for fatal exceptions
  • A few incompatibilities that previously silently disabled functionality are now fatal errors
  • Add Spanish translation of built-in strings
  • Fire onPartResourceListChange when changing resources


  • Recompile against KSP 1.4.5


  • Recompile against KSP 1.4.4


  • Fix ModuleJettison shroud disappearing in flight if used with a ModuleB9PartSwitch that affects drag cubes
  • Don't destroy info module in flight since that messes with module order


  • Recompile against KSP 1.4.3
  • Remove a couple of hacky workarounds as fixes/improvements were added in KSP 1.4.3
  • Use resource display names rather than identifiers in module description
  • Extract all hard-coded UI strings into localization table


  • Fix texture replacements getting locked in when loading a craft in the editor if a part up the hierarchy renders procedural drag cubes


  • Recompile against KSP 1.4.2
  • Fix transforms incorrectly being disabled in the part icon if subtypes are in a particular order
  • Fix transform in a TEXTURE node looking for renderers in child transforms too


  • Recompile for KSP 1.4.1


  • Fix texture replacements being reset when drag cubes are rendered
  • Fix battery tank type having 100x too much electric charge, bring mass in-line with stock


  • Add texture switching
    • Each subtype can now have TEXTURE nodes which take the following fields:
      • texture (required) - path to the texture you want to use, e.g. MyMod/Parts/SomePart/texture
      • currentTexture (optional) - name of the current texture (just the filename excluding the extension, not the full path). Anything that does not have this as the current texture will be ignored.
      • isNormalMap (optional, default false) - whether the texture is a normal map or not (necessary due to KSP treating normal maps differently when they are loaded)
      • shaderProperty (optional) - name of the shader property that the texture sits on. Default is _MainTex if isNormalMap = false or _BumpMap if isNormalMap = true. For an emissive texture you would want _Emissive
      • transform (optional, can appear more than once) - names of transforms to apply the texture switch to
      • baseTransform (optional, can appear more than once) - names of transforms where the texture switch should be applied to them and all of their children
    • If no transform or baseTransform is specified, it will look for textures to switch on the entire part


  • Only match on exact attach node id
  • When switching in flight, resources should always start empty
  • Allow individual subtypes to not allow switching in flight via allowSwitchInFlight field
  • Allow ModuleB9PartSwitch to have its GUI hidden if it has advancedTweakablesOnly = true and advanced tweakables are disabled
  • Better error handling if resource of tank type does not exist (show error dialog in game and force the user to quit)
  • Fix .version file not being able to be parsed by KSP-AVC
  • Move remote .avc file from bintray to s3
  • Add back assembly guid (accidentally removed a while ago)


  • Add new GUI that allows selecting subtype from a list
  • Allow switching in flight via switchInFlight parameter (uses new GUI)


  • Add stackSymmetry part field to subtypes


  • Fix drag cubes being overwritten with defaults on root part in flight scene
  • Fix vessel disappearing from map view if root part has a switcher that affects drag cubes


  • Recompile for KSP 1.3
  • Drag cube re-rendering now supports IMultipleDragCubes


  • Fix an occasional NRE when building part info


  • Allow "child" part switch modules to modify volume of "parent" module
  • Allow multiple modules to manage the same transform or node, only enable it if they all agree


  • Switch percentFilled priority to resource -> subtype -> tank type -> 100% since resources can be overridden on individual subtypes now


  • Allow tanks to be partially filled - percentFilled can be defined on the subtype, resource, or tank type (in decreasing order of priority), defaulting to completely full
  • Allow toggling resource tweakability in the editor - resourcesTweakable can be defined on the subtype or tank type (subtype takes priority), default is whatever the standard is for that resource
  • Allow RESOURCE nodes directly on the subtype
    • If the resource already exists on the tank, values defined here will override what is already on the tank (won't affect other subtypes using the same tank)
    • If it isn't already on the tank, it will be added (won't affect other subtypes using the same tank)
  • Add ModuleB9DisableTransform to remove unused transforms on models
  • Major internal changes


  • Recompile against KSP 1.2.2
  • Remove useless warnings in the log
  • A few internal changes


  • Recompile against KSP 1.2.1


  • Fix resource amounts displaying incorrectly in part tooltip
  • Reformat module title in part list tooltip a bit
  • Hopefully reduce GC some more


  • Update for KSP 1.2
  • Add CoMOffset, CoPOffset, CoLOffset, CenterOfBuoyancy, CenterOfDisplacement to editable part fields
  • Hopefully reduce GC allocation a little bit


  • Recompile against KSP 1.1.3
  • Remove some code which is unnecessary in KSP 1.1.3


  • Fix TweakScale interaction - resource amounts did not account for scaling (broken since v1.4.0)


  • Fix bug where we were setting maxTemp when we should have been setting skinMaxTemp or crashTolerance


  • Find best subtype intelligently
    • If subtype name was previously set, use it to find the correct subtype (allows subtypes to be reordered without breaking craft)
    • If name was not previously set or not found, but index was, use it (this allows transitioning from current setup and renaming subtypes if necessary)
    • If index was not previously set, try to infer subtype based on part's resources (this allows easy transitioning from a non-switching setup)
    • Finally, just use first subtype
  • Add unit testing for subtype finding
  • Get rid of some unnecessary logging in debug mode
  • Refactor part switching a bit


  • Fix bug where having ModuleB9PartInfo on a root part would cause physics to break due to an exception (really a stock issue but no sense waiting for a fix)


  • Do not destroy incompatible fuel switchers. Instead, disable fuel switching
  • Allow part's crash tolerance to be edited
  • Add info module to display changes to part in the info window. Only displays things that can be changed.
  • Various internal changes


  • Support TweakScale integration
  • Allow plural switcher description (in part catalog) to be edited)
  • Disable changing surface attach node size (problematic with Tweakscale)


  • Don't remove FSfuelSwitch or InterstellarFuelSwitch if ModuleB9PartSwitch doesn't manage resources
  • Defer rendering drag cubes until part has been attached (fixes flickering in editor)
  • Avoid firing events multiple times
  • Various internal changes


  • Recompile against KSP 1.1.2
  • Simplify part list info a bit
  • Hopefully make some error messages clearer
  • Various internal refactors and simplifications


  • Remove FSmeshSwitch and InterstellarMeshSwitch from incompatible modules
  • Recompile against KSP 1.1.1


  • Fix resource cost not accounting for units per volume on tank type


  • KSP 1.1 compatibility
  • Fixed bug where having part switching on the root part would cause physics to break
  • Moved UI controls to UI_ChooseOption
  • Adjust default Monopropellant tank type to be closer to (new) stock values
  • Use stock part mass modification
  • Hopefully fix incompatible module checking
  • Various refactors and simplifications which might improve performance a bit


  • Fix NRE in flight scene


  • Initial release
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