How to render paintExport in Houdini 12.5?

[magneto]

Hi,

I was looking at Peter Quint's Full Compositing series, where he adds an image plane in Mantra and chooses "paintExport" from the menu. But there is no paintExport in the same menu in Houdini 12.5. I tried all diffuse options listed in the menu and also typed paintExport manually but I didn't get the flat diffuse layer with no lighting like Peter did.

Anyone knows how to do this?

Thanks

[anim]

paintExport is probably custom image plane, mantra surface doesn't have just plain color export, maybe it was part of older materials or peter created one for that purpose

you can add your own but you need to dive into the shader and create the parameter VOP with export on, name it paintExport and plug in only color component of your material network

then manually type paintExport to image plane as VEX variable name on mantra node and set it to the same type as your exported variable like vector

you can use any name you like as long as you make sure it's not in conflict with already existing ones

[magneto]

Thanks anim, yeah it was definitely part of standard materials because Peter says so in the video around 13:50 of Part 2. I wonder why they were removed though. I will add them manually like you said.

Here is the video (embedding not allowed):

http://vimeo.com/13042237

Edited April 28, 2013 by magneto

[anim]

I guess it had something to do with unifying PBR and other render engines in H11

I'm not sure how easy it is to get pure color and pure diffuse lighting (without color contribution) in single render with PBR and still have resulting beauty pass looking correct (since not using color for diffuse, just exporting it white and color separately will get rid of all color bleeding and colored reflections but using it for diffuse makes it difficult to split them afterwards to export separately)

and because Surface Model VOP is using pbr_direct_lighting and therefore exports defined in pbrexports.h and pbrpathtrace.h even for non-pbr renders you cannot just split color and diffuse so easily there as well

what you can do is export your paint as a separate export and then divide diffuse (which contains both color and lighting) by it and hope you will get something like lighting contribution without color which you can use for some tweaks in your comp

or maybe there is some clever way to do it in surface model without customizing pbrpathtrace.h

[magneto]

Thanks anim. Here is how it looks in the video, so that's why I thought it was a simple thing to have/add. I didn't try yet but just showing

Edited April 28, 2013 by magneto

[anim]

it is and there is no problem with that for non PBR

I even think that peter is providing project files to the tutorials on his page so you may find the scene there

however if you are using mantra surface VOP or just it's parts like Physically Pased Diffuse VOP, Direct Lighting VOP, ... you will get lot's of PBR goodies like multiple importance sampling, but you will be limited for PBR exports regarding the diffuse, specular, ...

of course even that you can add your own exports like paint, or whatever, I was just saying about getting pure diffuse lighting without color which you usually need when you need pure paint color since you want to combine them later

but for custom non-pbr shaders you can do whatever you want and export any part before combining with other, just like on your screenshots

Edited April 28, 2013 by anim

[Peter Quint]

You are right - Paint Export was part of all the standard shaders up to H11, but was not included in the Mantra Surface Shader in H12 onwards. I did a video on passes in H12 that looks at some of the new workflows. You can add paintExport back by editing the Mantra Surfce Shader if you really need it.

Peter

[magneto]

Thanks alot guys, appreciate your replies. I didn't get a chance to try it yet, but I will very soon.

@Peter: I will check out your passes video immediately.