extra image plane and VEX builder bind

[tagosaku]

Hi, I was a vray artist, recently moved to Houdini, and have shader/rendering questions. (sample file: glassShaderBind03.hip)

1. (reference pic: extra image plane.jpg)
Are these check-boxes just preset? Are these check-box NOT automatically generated by available passes from materials in a scene, right? Then eventually I might need to find additional pass from VEX builder network and create/extract them by filling out VEX variable?

2. (reference pic: glass_All.jpg, bind.jpg, extra image plane.jpg)
I try to create extra image plane like a vray render elements. Let's focus on my glass objects(mantraSurface shader). I used some preset check-box to generate extraImagePlanes. Then, when I combine spec pass, refract pass and reflection pass in a compositing software, it should become the full image because I only use reflection, refraction, and opacity settings. However it's still missing some layers, and especially spec pass is broken, too. I think I need to dive into VEX builder to fix a sort of spec-output-node and also create new bind or parameter nodes in order to generate proper reflection and refraction passes?! I have really no idea about this system!

3. (reference pic: glass_spec11P.jpg, glass_mantra01P.jpg)
When I set roughness >0, I can get nice specs. However, render-time gets 3-8 times heavier with opacity. Do we have any optimization in shader and mantra-setting?
 

Thanks!

glassShaderBind03.hip

Edited August 24, 2016 by tagosaku

[merlino]

Hi Tagosaku, for my (little) experience with rendering, the artifact you see in the spec_clr pass it's probably due to the fact that "preview" is enabled. Try disble it, some time it gives met hat kind of artifact.

[tagosaku]

Preview ON/Off doesn't fix at all, sorry. Anyway, I thought my questions were simple, but could be very difficult because nobody has responded yet, LOL.