Setting up render passes Houdini 11

[Barakooda]

Hello!

I`m start to render more and more this days with Houdini,

if some one can direct to easy and comfort way to Set up render passes in Houdini 11 it will be great.

I`m work on little project (with no passes)

http://www.sidefx.co.il/wp-content/uploads/2011/04/pp3.jpg

I`m sure its general question that many users looking for answer and example which not really exist(as far as i looked) in sidefx.com web site.

I added simple file to implement the example on it .

thanks !

B.

render_pass_try.hipnc

[dayvbrown]

Hey hey,

So having a quick look through your file it appears you're pretty much set up to export passes.

Now to be clear you are talking about exporting diffuse\spec etc, rather than separate objects. If that's the case then it's a really simple process.

Because you're using the surface model shaders (they are within the materials you've put down) they already have AOV's setup and can be called from the mantra Rop with no further work. I can see you've already set up the rop to output N (under "Properties\output\Extra Image Planes") and all you need to do is add additional image planes to the rop and select the pass you want from the dropdown menu of "VEX Variable". There are a number there that are already setup with the surface model vop.

Things to note -

*You need an image plane for each pass.

*If you want to save out different files for each pass (rather than say a layered .exr) turn on the "Different File" checkbox (you'll need to be saving an output picture to do that rather than rendering to mplay) and put in the filename.

If you want to create your own passes then you'll need to be building them into the shader. I'm sure if you do a search for AOV's you should be able to find some tutes.

If you want to have a look at the existing ones go to your materials (clay will be the easiest one), jump inside, and then select the surface model and jump inside again. You'll see big mess of wires but if you look just below the biggest one you'll see a bunch of "parameter" nodes coming out from a "Direct Lighting" node. These are some of the outputs that are setup. Take note of the "Name" parameter and you'll see that's what you're calling in the mantra Rop. This is how aov's are setup, you use a parameter vop and call it with your mantra. Don't let the complication of the surface model scare you away, you can create usable shaders with ALOT less nodes than that

Hope this helps.

Dave.

[Barakooda]

Thanks mate !

I see that I can output any vector that way,

Now,

there are different ways of having ambient occlusion pass, what are the most convenient one ?

right now i find my self change material to all objects to nothing (i guess its clay by default ?) and use the environment light AO mode to get this pass also i know the light template method with global illumination shader...

(still need to see how i`m taking "takes" in houdini)

There is any faster way of doing it ?

or that the the usual main stream artist work flow ?

[Erik_JE]

Thanks mate !

I see that I can output any vector that way,

Now,

there are different ways of having ambient occlusion pass, what are the most convenient one ?

right now i find my self change material to all objects to nothing (i guess its clay by default ?) and use the environment light AO mode to get this pass also i know the light template method with global illumination shader...

(still need to see how i`m taking "takes" in houdini)

There is any faster way of doing it ?

or that the the usual main stream artist work flow ?

Some weeks ago i found some thread here on odforce that talked about adding the shop_disable_surface_shader parameter to the mantra rop. Then when rendering it will only use the displacement shaders of the materials. This combined with an environment light set to AO makes for an easy ambient occlusion pass.

Edited May 12, 2011 by Erik_JE

[dayvbrown]

Thanks mate !

I see that I can output any vector that way,

Now,

there are different ways of having ambient occlusion pass, what are the most convenient one ?

right now i find my self change material to all objects to nothing (i guess its clay by default ?) and use the environment light AO mode to get this pass also i know the light template method with global illumination shader...

(still need to see how i`m taking "takes" in houdini)

There is any faster way of doing it ?

or that the the usual main stream artist work flow ?

As with everything there are many many ways of achieving this.

As Erik_JE has said it can be done that way, you could also put down and Occlusion vop in your shader and export it the same way as the other passes. Ie: put down a parameter vop call it something like occlusion and export through mantra. Don't have houdini in front of me at the moment but you'll need to change the environment tint or bg colour (can't remember) to 2,2,2 to get a nice range of black - white. You can play around with your Maximum Ray Distance and Samples to speed it up.

Dave

[Barakooda]

As with everything there are many many ways of achieving this.

As Erik_JE has said it can be done that way, you could also put down and Occlusion vop in your shader and export it the same way as the other passes. Ie: put down a parameter vop call it something like occlusion and export through mantra. Don't have houdini in front of me at the moment but you'll need to change the environment tint or bg colour (can't remember) to 2,2,2 to get a nice range of black - white. You can play around with your Maximum Ray Distance and Samples to speed it up.

Dave

thanks

i will try , actually i tried to make AO parameter :-)

Edited May 13, 2011 by Barakooda

[dayvbrown]

thanks

i will try , actually i tried to make AO parameter :-)

sorry i should clarify - there is a node called "Occlusion" that you'll need to put down and then connect that to a parameter node, naming the parameter node "AO" or whathaveyou and export that. not sure if that was too clear in the last rambling post

[Barakooda]

sorry i should clarify - there is a node called "Occlusion" that you'll need to put down and then connect that to a parameter node, naming the parameter node "AO" or whathaveyou and export that. not sure if that was too clear in the last rambling post

Thanks mate , it was clear ! (just saw you comment again)

And to get AO pass as most artists use to, you should change the background parameter to 2,2,2 as you said.

B.

Edited May 26, 2011 by Barakooda