thank you. :yes:
The bi-dir integrator crashes with a scene exported from Blender (.dae). Here the scene but with uni-dir pathtracer
The bi-dir produced nice caustics as expected but failed to finish the render sadly.
The exporter sounds cool Jose!
Oh great! Thank you so much for working on it, looking forward to it!
Wouldn’t the sun part of a sun/sky lamp generate rays? At least (sharp) caustics can often be generated from sun lamps, and that usually requires Bi-Dir to be used? Or perhaps I misunderstood, after all, I don’t write or modify render engines 
Yes, but how did you generate random ray from background or sun ? Propability to hit something will be near 0.
Hmm, I’m not sure really, I just know that with the LuxRender, and Yafaray sun lamps can produce sharp caustics. Wouldn’t they be the rays cast from the (sun) lamp in the Bi-Dir (for Lux) and via Yafaray’s photon mapping?
I believe that there is a method in Mitsuba to approximate mesh lamps at render time based on an HDR background image. At least, Wenzel was involved with a paper that explains how to do it and I assume he’d implement it into his engine.
Some tests with Mitsuba, just playing around. The bi-dir keep crashing sometimes. The glass object is imported from Blender.
In the mat preview scene i used a sunsky plugin. For the glass and envmap+area light
Bi-dir
PathTracing
PhotonMapping
Bi-dir
how does the Hair rendering development (mitsuba-hair) work?
your awesomeness is showing 
I expected more “quality” from the bi-dir integrator, shouldn’t it be really clean and with nice crisp caustics? Previous tests show a fireflies mess.
Here are some SSS test with PT integrator. Dipole plugin, skin1 preset:
scale 0.05
scale 0.2
scale 0.8
Try using the dipole SSS with the rough plastic BSDF, the results are a lot more skin-like. Also, I have no idea what you did, but I’ve never gotten results that poor from the BiDir integrator in Mitsuba. It could also be because BiDir isn’t meant to be used in open scenes because it makes it very hard for rays to be traced back and forth between light sources and the camera. Where you will see the best results are in closed rooms, especially with lots of bounce lighting or light coming from small sources. Also keep in mind, BiDir isn’t a panacea for rendering problems. Much work has been done over the years to make BiDir as robust in corner cases as plain path tracers, and we’re still not there yet. Wenzel is definitely on the cutting edge with some of the algorithms he’s implemented though.
I tried with roughplastic, really cool results. About poor dielectric results, give a try when you can and post results if you can, i used the standard matpreview scene, changed material to dielectric (all default values), and changed the envmap with the sunsky plugin.
hey all, i’ve hacked my way through the exporter and got it working for the newest version, i just don’t know how to get the Dipole bsdf to work. so until JoseConseco spruces it up, if anyone would like to try a mostly-working exporter i can upload it
Gorgeous, marcoG_ita. What are your render times/CPU?
Does the exporter output .xml format? If so, the dipole material is pretty easy to set up as long as you’re using presets.
Thanks Sanne, few minutes with core i7, PathTracer integrator, 64 samples IIRC.
Cheers
I really wish I could help with making an exporter. Have you tried sending emails to anyone that might be interested in taking the exporter further?
Mitsuba is quite a nice renderer but sadly lacks a GUI still and I wish I had time to learn how to code better >.>
would you, by any chance, be willing to take a quick look at exporting the other sensor types? i’m looking at how to modify the exporter to export the ‘thinlens’ sensor since that’s the only one really useful to me personally, since it supports DoF (and i think without exporting a sensor explicitly, it’s defaulting to the ‘perspective’ sensor).
also, how would one set it so that only active layers are exported?
Thanks, good render times. I would have thought SSS takes longer.
When I try to use the dipole plugin mitsuba always hangs and I have to force quit. I guess I’m doing something wrong. Would you share the xml file of your SSS scene? I’d like to take a look at how you set up the material.