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LPE EventsDescriptionExample
<type event 'group'>
Scattering event specified by scattering type, scattering event, or lpe groupC<.[DS]'floor'>[LO] matches all light paths from the floor lpe group
Light, i.e. analytic and geometric lightsC[DS]*<L.'key'> matches all light paths from the key light group
Emissive object, i.e. camera visible lights and material glowC[DS]*O matches all emissive object light paths
A period will match any relevant event<.D> where the period represents R or T
Scattering Types  
ReflectionC<R[DS]>[DS]*[LO] matches all reflected light paths
Transmission or refractionC<T[DS]>[DS]*[LO] matches all transmitted light paths
Scattering Events  
Diffuse lobes (D1 to D4)CD[DS]*[LO] matches all diffuse light paths
Specular/Glossy lobes (S1 to S8)CS[DS]*[LO] matches all specular light paths
User lobes used to output material properties (U1 to U12)CU2L matches the camera visible user2 lobe, typically albedo
( )Parentheses allow grouping of a sequence of LPE eventsCDSL, C(DS)L, and CD(SL) are all functionally the same
|A vertical bar separates alternativesCD|(SD)L matches direct diffuse or specular-diffuse light paths
[ ]Square brackets that match any one of the enclosed eventsC[D2D3]L matches direct diffuse2 or diffuse3 light paths
[^ ]
Square brackets that match any one event not contained within the bracketsC[^D2D3]L matches all light paths besides diffuse2 and diffuse3 (including specular and user)
An asterisk will match the preceding event zero or more timesC[DS]*[LO] matches all light paths, including emissive
A plus sign will match the preceding event one or more timesC[DS]+[LO] matches direct and indirect light paths, but not emissive
Curly brackets that match the preceding event exactly n timesC<T[DS]>{2}[LO] matches double transmission light paths
Curly brackets that match the preceding event min or more timesC[DS]{2,}[LO] matches all indirect light paths
Curly brackets that match the preceding event at least min but not more than max timesC[DS]{0,1}[LO] matches direct and emissive light paths


An LPE group (lpegroup) allows us to specify which objects we want to be use for an LPE channel. The attributes can be added in RenderMan plugins using the software's menu system such as PrmanObjectSettings in Katana.


Code Block
/prman/lpe/user2                 Albedo,DiffuseAlbedo,SubsurfaceAlbedo,HairAlbedo


  • In the documentation examples we often use <L.> in place of L. There's no functional difference.
  • lpe:CD<L.> means camera with diffuse scattering event for light scattering type.
  • lpe:CO means camera with emissive objection (since emissive does not need any light, there is no L).