Hey I'm new here and in Houdini but I have small project which I wanna render but I dont know what should I did to render scene without black background because I want to composite this scene in AE.

The black background is almost the only way to render. It is the standard way to use a render in a compositor.

Ok thanks I have saved 1 frame for test in exr format but I dont know why when i press Render in mantra node rendering was in the background and I see this process only in Windows Task Manager.In EXR file colors was a little bit different than in Houdini.

Yep - that sounds correct -when you render to a file Mplay will not show.

Hokmah
Ok thanks I have saved 1 frame for test in exr format but I dont know why when i press Render in mantra node rendering was in the background and I see this process only in Windows Task Manager.In EXR file colors was a little bit different than in Houdini.

When you press render , a new window will open to show your rendering progress (percentage of your render ) , Not only in the Task manager !!!
is it open for you ?
Also if you use simple ip text in the Output Picture parameter for Mantra node , you can see full rendering process in mPlay , But don't forget to save these images to the disk (Use File->Save Sequence As in the mPlay window) , Because they will lost if you close mplay after finishing rendering.

About changing color in Houdini and your exr format , I think that's because different color space in the Houdini and your compositing software.the color space in Houdini is Gamma 2.2 , So you should set Gamma to 0.04545 ( 1 / 2.2 ) in the composite for your exr file to back it to gamma 1.
:wink:

Thanks for answers Everything is ok now but i have one more question if I will render all my layers like foam,spray,ship in one time for EXR format I will get channels for post production for all layers forum Houdini or I should render separately foam, separately spray… Below test render )

No ,You can setup Channels for only one Mantra node , Then Houdini will render them one time in one exr file.(Actually this is multiple time in one exr !)
you should go to your mantra node and add Extra Image Plannes in the Properties->Output

You can simply add different passes for lighting (Indirect + Direct) , Z depth , Position , Normals , Reflection , Refractions and etc.

But if you wanna render foam , spray , ocean and etc in the separate pass ,You should do some changes on your project to export these data from Geometries and Material to the Mantra node , then call these data for rendering in the Extra Image Planes.

for example suppose you wanna have different passes for ObjectIDs .
So you can add a custom attribute with same name (e.g JKID) and different value for each object (Foam , Spray , Ocean) , Then export this attribute in the shader (Add a Parameter VOP node and set name to JKID and set Export parameter to Always).

Then add new Extra Image Planes and Set VEX Variable to JKID .

Finally the Mantra take JKID value for each object with it's material and it's Point/Primitive attribute and render this value in the Image !

If doing this operation is hard and complex for you (until you learn it) ,I suggest you render each one in different EXR file ,If you use Takes , this is not very hard :wink:

Yes I think i will create few mantra nodes for foam,spray,animation and render each one in different EXR and I think will be the best way at this moment for me And last one question.. I have one EXR file but i cannot unlock this layer in PS and add new layer and I dont know why.

Photoshop ?
I don't use PS for compositing , I usually using Nuke , But which layer you can't use ?
I test it on a simple exr file without any problem , I just open it in the PS and add new layer on it !

Yeah but I dont have Nuke but I will try in AE or Fusion. I can't use any layer and I can't add new layer.. Check on screen below it is locked and i can't unlock this layer.

I'm not using PS but check the Channels tab - they Exr ‘layers/channels’ are probably there.

That Background layer is always locked

To unlock background layer in PS , Just double click on it and in the new window which opened , press OK button.

Also if a window (EXR Read Options) opened in the first time , choose "As Transparency" option . in this case Alpha channel use for Transparency in the Layers section.

Another important note is you can just access to Alpha channel (if second option of EXR Read Options activated) in the Channels section ,not Z Depth , Position pass , Normal Pass or similar !

Try to use some Compositing software such as AE ! :wink:

Yep I know how to unlock PS layer but in this case it doesn't work. All options are grey.. it is only 1 frame because for render this scene in 1280x720 i will need lot of time so I decided to make few good shots with post production

Hokmah
Yep I know how to unlock PS layer but in this case it doesn't work. All options are grey.. it is only 1 frame because for render this scene in 1280x720 i will need lot of time so I decided to make few good shots with post production

Sorry about that man :roll: ops:



If you can't fix it , upload 1 frame of your exr's , let me check it on my PS :wink:

No problem mate In attachment you can see my EXR file.

That's strange !
I opened your EXR on my PS and unlocked it without any problem !
I really don't know what happening for your PS :shock:

I'm using PS CS6 :!:

I have CS6 too and can't unlock this layer.. So we found reason of that problem I will make compo in Fusion. Thanks for help.a