Improve Bind Pose Support in Blender #50412

New Issue

Gaia Clary · 2017-01-11T00:30:16+01:00

Gaia Clary commented

2017-01-11 00:30:16 +01:00

This task is directly related to the task #38660

Back in Blender 2.70 we had a nasty problem with exporting data from Blender to Secondlife. The problem was that we necessarily needed to support the Bind Pose feature. That is:

The Restpose is where all pose matrices are neutral have no influence on the skeleton and the meshes
The Bindpose is an arbitrary pose that is treated as if it where the restpose.

But Blender does not have a bind pose, or better said, In Blender the Bindpose and the Restpose are always identical.

Back in 2.70 this issue was solved in a very ugly way:

we added a custom transformation to each bone which contains a scale, a rotation and a translation:

  restpose_scale_x (default = 1.0)
  restpose_scale_y (default = 1.0)
  restpose_scale_z (default = 1.0)

  restpose_rot_x (default = 0.0)
  restpose_rot_y (default = 0.0)
  restpose_rot_z (default = 0.0)

  restpose_loc_x (default = 0.0)
  restpose_loc_y (default = 0.0)
  restpose_loc_z (default = 0.0)

So if any of those value sets exists then the Blender collada exporter will use the found data (the bindpose) to define the "inverse bind matrix of the bone"

So far so well, now we have the opposite issue. We must preserve the bind pose data when a skeleton is imported into Blender. But currently Blender just takes the bindpose that comes with Collada and creates a restpose out of it. So it actually "applies the current pose as new restpose" and so all bindpose information goes away and can not be recoveres.

So my idea is:

Let the Collada Importer fill in the bindpose matrices into the custom properties. And make it so compatible with what we already have (use the custom properties restpose_scale_x/y/z etc as we have already for the exporter)

I believe this addition can be easily implemented and it would make the Importer able to import bindpose information and keep it for later reuse (for whichever purpose, not only for later export).

Implementing this would be straight forward. The bind pose data is available in the function where the restpose is calculated from the Collada data. At this point it is easy to also generate the customproperties. It should be a matter of a couple of hours to get this basically working. Well, ok maybe 2 days for me :).

But maybe this can be made more general and useful, it even could be used to implement a true Bind Pose support in Blender (just like Maya has for example and just like Collada supports it).

Please let me know how to proceed from here.

cheers,
Gaia

This task is directly related to the task #38660 Back in Blender 2.70 we had a nasty problem with exporting data from Blender to Secondlife. The problem was that we necessarily needed to support the Bind Pose feature. That is: * The Restpose is where all pose matrices are neutral have no influence on the skeleton and the meshes * The Bindpose is an arbitrary pose that is treated as if it where the restpose. But Blender does not have a bind pose, or better said, In Blender the Bindpose and the Restpose are always identical. Back in 2.70 this issue was solved in a very ugly way: we added a custom transformation to each bone which contains a scale, a rotation and a translation: ``` restpose_scale_x (default = 1.0) restpose_scale_y (default = 1.0) restpose_scale_z (default = 1.0) ``` ``` restpose_rot_x (default = 0.0) restpose_rot_y (default = 0.0) restpose_rot_z (default = 0.0) ``` ``` restpose_loc_x (default = 0.0) restpose_loc_y (default = 0.0) restpose_loc_z (default = 0.0) ``` So if any of those value sets exists then the Blender collada exporter will use the found data (the bindpose) to define the "inverse bind matrix of the bone" So far so well, now we have the opposite issue. We must preserve the bind pose data when a skeleton is imported into Blender. But currently Blender just takes the bindpose that comes with Collada and creates a restpose out of it. So it actually "applies the current pose as new restpose" and so all bindpose information goes away and can not be recoveres. **So my idea is:** Let the Collada Importer fill in the bindpose matrices into the custom properties. And make it so compatible with what we already have (use the custom properties restpose_scale_x/y/z etc as we have already for the exporter) I believe this addition can be easily implemented and it would make the Importer able to import bindpose information and keep it for later reuse (for whichever purpose, not only for later export). Implementing this would be straight forward. The bind pose data is available in the function where the restpose is calculated from the Collada data. At this point it is easy to also generate the customproperties. It should be a matter of a couple of hours to get this basically working. Well, ok maybe 2 days for me :). But maybe this can be made more general and useful, it even could be used to implement a true Bind Pose support in Blender (just like Maya has for example and just like Collada supports it). Please let me know how to proceed from here. cheers, Gaia

Gaia Clary commented

2017-01-11 00:30:16 +01:00

Changed status to: 'Open'

Gaia Clary commented

2017-01-11 00:30:16 +01:00

Added subscriber: @GaiaClary

Gaia Clary commented

2017-01-11 00:35:37 +01:00

Added subscribers: @JoshuaLeung, @Sergey, @mont29
Removed subscriber: @GaiaClary

Added subscribers: @JoshuaLeung, @Sergey, @mont29 Removed subscriber: @GaiaClary

Gaia Clary commented

2017-01-11 00:35:37 +01:00

Please can you comment on this and help me deciding how to proceed? thanks a lot !

Gaia Clary commented

2017-01-11 10:30:40 +01:00

Added subscriber: @jesterking

Gaia Clary commented

2017-01-11 10:30:40 +01:00

No description provided.

Nathan Letwory commented

2017-01-11 11:32:56 +01:00

I suppose for now using Custom Properties during import would do fine, but @JoshuaLeung can probably tell more about tackling this in a better way.

Bastien Montagne commented

2017-01-11 12:00:44 +01:00

Well… Adding the different restpose/bindpose concept into Blender would be a really big project (would likely affect a lot of editing/posing armature tools), and, more importantly, I personally do not understand why this is needed at all? What are the benefits, the things you cannot do without that dichotomy?

Note that currently, in FBX, we are assuming that rest pose is same as bind pose (in other words, we use FBX's bindpose as restpose as well). Tbh, I would be reluctant diving into that nightmare again, we already have waaaayyyyyy to much things to handle in FBX’s transform & rigging system. ;)

But you are obviously free to support that in Collada IO! I think your current idea is the best way to do so, especially since it’s already hooked into exporting code.

Well… Adding the different restpose/bindpose concept into Blender would be a really big project (would likely affect a lot of editing/posing armature tools), and, more importantly, I personally do not understand why this is needed at all? What are the benefits, the things you cannot do without that dichotomy? Note that currently, in FBX, we are assuming that rest pose is same as bind pose (in other words, we use FBX's bindpose as restpose as well). Tbh, I would be reluctant diving into that nightmare again, we already have waaaayyyyyy to much things to handle in FBX’s transform & rigging system. ;) But you are obviously free to support that in Collada IO! I think your current idea is the best way to do so, especially since it’s already hooked into exporting code.

Gaia Clary commented

2017-01-11 12:29:51 +01:00

Thanks for feedback so far!

So i proceed as follows now:

I add the code for creating the custom properties to the Collada importer
I add an option to the importer to "import bind pose info"
I also add a new option to the exporter "use custom bind pose"

Optionally add 2 new operators for:

generate bind pose info from current pose
delete bind pose info from active armature

Those operators can be accessed from the SPACE menu.

Optionally (if that is possible):

add 2 buttons into the Custom Properties section of armatures to access the operators. This can either be made directly in Blender or i can put this into a small Addon if that is more convenient.

Thanks for feedback so far! So i proceed as follows now: - I add the code for creating the custom properties to the Collada importer - I add an option to the importer to "import bind pose info" - I also add a new option to the exporter "use custom bind pose" Optionally add 2 new operators for: - generate bind pose info from current pose - delete bind pose info from active armature Those operators can be accessed from the SPACE menu. Optionally (if that is possible): - add 2 buttons into the Custom Properties section of armatures to access the operators. This can either be made directly in Blender or i can put this into a small Addon if that is more convenient.

Gaia Clary commented

2017-01-11 13:20:19 +01:00

Added subscriber: @GaiaClary