Light emitting particles and photon mapping

Component:YafaRay Core
Category:bug report


I just found an issue in 0.1.2 and 0.1.3 (using both Blender 2.62 and 2.63) -- if I create object with "Enable meshlight" option set and then use it in particle system as a particle, the only render mode which renders light out of particles correctly is "Path tracing". Neither SPPM, nor Bidirectional nor any other show any light at all. Any of photon-mapping render methods print out error message: 

INFO: SPPM: Rendering pass 1 of 1000...
INFO: SPPM: Starting Photon tracing pass...
INFO: SPPM: Light(s) photon color testing for photon map:
INFO: SPPM: Building photon map...
ERROR: SPPM: lightPDF sample error! 0/0... stopping now.

Bidirectional render is not possible, because it can't find any light source.

I've tested with GPU enabled photon mapping in 0.1.3 -- same issue.

2012-07-01_225119.jpg165.36 KB
2012-07-01_225520.jpg148.56 KB




Testing this issue on the current version of yafaray, there seems to be a regression compared to the original report.  With meshlight objects rendered as particles I get a black render with all integrators, even pathtracing.  Photon mapping integrators report the error as described in the original post.

I decided to test if object instancing plays a role by creating regular instanced objects with the meshlights (using alt-D).  With this scene all renders are black too, but if the option to export instances is unchecked in the exporter then the scene appears to render normally.  Disabling instancing does not work with the particle scene.

I am attaching both the particle scene and the regular intances file for testing purposes.

meshlight-particles.blend 549.11 KB
meshlight-instances.blend 480.36 KB
meshlight-instances.png 217.37 KB


Status:active» postponed