Blender does not properly handle EXRs with both named and un-named layers #34174

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Jason Clarke · 2013-02-09T03:37:21+01:00

Jason Clarke commented

2013-02-09 03:37:21 +01:00

%%%--- Operating System, Graphics card ---
Mac OS X 10.8.2, ATI 5770

- Blender version with error, and version that worked ---

r54366M x64 (2.66rc1)

- Short description of error ---

Blender does not seem to properly handle multilayer OpenEXR files that also contain an unnamed layer. This may be due to the fact that Blender does not itself generate such a file that I've found. However, Maya likes to spit them out, by only labeling passes other than MasterBeauty (equivalent to the "combined" pass in Blender). This makes using Blender's compositor with Maya renders a bit difficult.

The bug comes in two forms:

If the file contains 1 named layer and 1 unnamed layer, Blender will treat it as a single-layer EXR, the named layer will be ignored.

If there is more than 1 named layer, Blender will treat it as a multi-layer EXR, and the unnamed layer will be ignored.

As a result, you are never able to load all passes into the compositor. For example, there's no way whatsoever to do DoF in the compositor on a Maya render without rendering each pass to a separate file, as there is no way to load the combined and depth layers into the compositor simultaneously.

- Steps for others to reproduce the error (preferably based on attached .blend file) ---

You can find a sample EXR file here (tracker doesn't seem to like it as an attachment): htp://dtc-wsuv.org/jclarke/exr_layer_bug_masterLayer_persp.exr

It contains a primary layer (that is not named), then depth and AO passes on named layers. You can view all 3 layers correctly by opening the file in DJV (http://djv.sourceforge.net/). If you load the file into the image editor, the main layer will not be seen, Blender will only see the depth and AO passes, and claims there is nothing else in the file.
%%%

%%%--- Operating System, Graphics card --- Mac OS X 10.8.2, ATI 5770 - Blender version with error, and version that worked --- r54366M x64 (2.66rc1) - Short description of error --- Blender does not seem to properly handle multilayer OpenEXR files that also contain an unnamed layer. This may be due to the fact that Blender does not itself generate such a file that I've found. However, Maya likes to spit them out, by only labeling passes other than MasterBeauty (equivalent to the "combined" pass in Blender). This makes using Blender's compositor with Maya renders a bit difficult. The bug comes in two forms: If the file contains 1 named layer and 1 unnamed layer, Blender will treat it as a single-layer EXR, the named layer will be ignored. If there is more than 1 named layer, Blender will treat it as a multi-layer EXR, and the unnamed layer will be ignored. As a result, you are never able to load all passes into the compositor. For example, there's no way whatsoever to do DoF in the compositor on a Maya render without rendering each pass to a separate file, as there is no way to load the combined and depth layers into the compositor simultaneously. - Steps for others to reproduce the error (preferably based on attached .blend file) --- You can find a sample EXR file here (tracker doesn't seem to like it as an attachment): htp://dtc-wsuv.org/jclarke/exr_layer_bug_masterLayer_persp.exr It contains a primary layer (that is not named), then depth and AO passes on named layers. You can view all 3 layers correctly by opening the file in DJV (http://djv.sourceforge.net/). If you load the file into the image editor, the main layer will not be seen, Blender will only see the depth and AO passes, and claims there is nothing else in the file. %%%

Jason Clarke commented

2013-02-09 03:37:21 +01:00

Changed status to: 'Open'

Ton Roosendaal commented

2013-02-09 15:25:55 +01:00

%%%Let me check this.

However, if you make maya give layers a name, does it all work fine?
In blender the layer name is used to map things, so it needs to be unique names preferably.

Long ago (2005!) I proposed to the openexr group to define a convention for layer+pass names, to allow interoperability better. That wasn't accepted.
At that time, Blender was the first to support this even :)%%%

%%%Let me check this. However, if you make maya give layers a name, does it all work fine? In blender the layer name is used to map things, so it needs to be unique names preferably. Long ago (2005!) I proposed to the openexr group to define a convention for layer+pass names, to allow interoperability better. That wasn't accepted. At that time, Blender was the first to support this even :)%%%

Ton Roosendaal commented

2013-02-09 17:54:15 +01:00

%%%Hi Jason,

Having a primary layer just with names "R" "G" B" "A" in openexr seems to be quite common. it allows standard viewers to show something as well.
I've added support for this in Blender now too. It shows menus for browsing layers and passes without a name now, a bit weird - but at least this works fine.

Is in svn now, and you will get it in the RC and release within a week!%%%

%%%Hi Jason, Having a primary layer just with names "R" "G" B" "A" in openexr seems to be quite common. it allows standard viewers to show something as well. I've added support for this in Blender now too. It shows menus for browsing layers and passes without a name now, a bit weird - but at least this works fine. Is in svn now, and you will get it in the RC and release within a week!%%%

Ton Roosendaal commented

2013-02-09 17:54:15 +01:00

Changed status from 'Open' to: 'Resolved'

Ton Roosendaal closed this issue

2013-02-09 17:54:15 +01:00

Ton Roosendaal commented

2013-02-09 18:04:04 +01:00

%%%BTW: the fix is for the primary layer.

The file also has an unknown pass customDepth ... not sure what this is?

For multilayer, blender sticks to strict ordering of layer name + pass name + channel. Now if we could figure out what's "standard" now...%%%

%%%BTW: the fix is for the primary layer. The file also has an unknown pass customDepth ... not sure what this is? For multilayer, blender sticks to strict ordering of layer name + pass name + channel. Now if we could figure out what's "standard" now...%%%

Jason Clarke commented

2013-02-09 18:07:04 +01:00

%%%Awesome, thanks!

Btw, for anyone coming along and seeing this through Google or whatever, I thought I should add something about Maya's layer naming: as far as I know, it will always have an "R" "G" B" "A" ("unnamed") layer. By default, it will also give the layers names that don't match up with Blender's convention. They'll load fine, but you'll get weirdness like the layer/pass menus in Blender giving you a choice of camera. You can get Maya to name the layers the way Blender expects by going to the Render Globals > Common tab, turning on custom framebuffer naming, and changing it to: .%%%

%%%Awesome, thanks! Btw, for anyone coming along and seeing this through Google or whatever, I thought I should add something about Maya's layer naming: as far as I know, it will always have an "R" "G" B" "A" ("unnamed") layer. By default, it will also give the layers names that don't match up with Blender's convention. They'll load fine, but you'll get weirdness like the layer/pass menus in Blender giving you a choice of camera. You can get Maya to name the layers the way Blender expects by going to the Render Globals > Common tab, turning on custom framebuffer naming, and changing it to: <RenderLayer>.<RenderPass>%%%

Jason Clarke commented

2013-02-09 18:15:05 +01:00

%%%customDepth pass was me hitting the wrong button when making the file. I meant to hit "CameraDepth" next to it in the menu, which is a pass Mental Ray has for getting the z-buffer. I switched the type to camera depth before actually rendering this file, but when you make a new pass in Maya, it creates a node/datablock to represent it (named for the pass type by default) and its settings, and the pass name string apparently takes the name of this node, not the name of the pass type.%%%

Ton Roosendaal commented

2013-02-09 18:21:54 +01:00

%%%Thanks for the info, I've resent my request to the OpenEXR list about mapping out together what the used conventions are, and if we could align this a bit. %%%

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Blender does not properly handle EXRs with both named and un-named layers #34174