aaronfranke
commented
1 year ago As a concept I wholeheartedly agree, but let's take our time with this, implementing it over many years. We'll likely want to have Godot-specific extensions for information highly specific to Godot, in fact we have already reserved the GODOT_ vendor prefix. However, if we can have more information in a format that's portable between engines then that's ideal, and have a minimal amount of information in a Godot-specific format.
Some examples are physics settings, camera/light settings ... or enabling collisions
Cameras are part of the base glTF spec. Lights are covered by KHR_lights_punctual.
Physics is covered by OMI_collider, OMI_physics_body, OMI_physics_joint, soon OMI_physics_material, and eventually some OMI extensions for vehicles and wheels (I see you're aware of OMI_physics_body already).
Note that we could still make a GODOT_ extension that sits on top of OMI_physics_body if we wanted to have more Godot-specific data like damping, sleeping, contact monitor, etc, and other apps would still be able to load the OMI_physics_body data even if they don't support the GODOT_ extension. However, we should only do this if we think it's necessary and helpful and will stand the test of time. Just the OMI specs should be good enough.
shader node setup, or splines ... such as LOD settings ... or via import hints in object names.
These might be good candidates for a specific GODOT_ extension, but I'm not an expert in these so I can't say for sure. If there is a way to specify shader nodes, splines, LOD, animation looping, navigation meshes, etc in a generic way we should do that.
I believe that if you opt into using the add-on, the Advanced Import dialog is no longer necessary ...
It will still be available of course, but the goal here is to allow as many things as possible to work without it, since we should be able to transfer any data we want from Blender via GLTF and there will be no need to tweak things in the advanced import dialog.
The ideal solution would be to grey out all settings in this dialog that are managed by the add-on, with a hint text informing the user to use Blender to modify these settings instead.
I disagree with this part, there is no need to prevent overriding what's in the file if you want to do so. The data in the file is optional, you should not be forced to use it. Keep in mind that you might now have Blender installed and want to tweak a model later, or maybe someone else made the model and just sent you the GLTF file.
Alternatively, we would need an option for Blender to load the .import files to synchronize Godot changes back into Blender. This can probably not be done automatically, but is instead done via a button.
That sounds like a separate thing though, making Blender read Godot's import config files isn't required to make Blender add more data to the GLTF file and have Godot read it.
Import hints like -col etc. should be ignored as well.
Disagree, it's harmless to keep it, I don't see any strong reason to disable that feature.
Is there a reason why this should be core ... Debatable, so please discuss!
Indeed, that's the big question. It totally does not need to be in the engine, the only reason we would do that is to encourage it as the official way since users would not have to hunt down an extension. However, considering that users would already have to hunt down a Blender extension maybe it's not a big deal. Though it may be the case that the user providing the GLTF files from Blender is a different user from the one importing into Godot.
If we do have GODOT_ prefix extensions, those should be maintained inside the Godot organization, either in the engine or a separate repo we put up officially on the Asset Library, not on someone else's GitHub account.
RedMser
fire
Describe the project you are working on
Any 3D project using Blender for asset creation
Describe the problem or limitation you are having in your project
Supersedes #2422
Note that "add-on" refers to Blender's add-on system, and not Godot's EditorPlugins.
As already mentioned in that issue, many features of Blender do not get imported into Godot. Some examples are physics settings, camera/light settings, shader node setup, or splines. This is due to the glTF exporter not supporting such features, and .blend files are imported through the glTF pipeline.
Furthermore, certain options are Godot-specific and are not even part of Blender's UI, such as LOD settings or enabling collisions. These must currently be configured using the Advanced Importer or via import hints in object names.
Describe the feature / enhancement and how it helps to overcome the problem or limitation
The goal is to
This is done by creating an add-on for Blender that can be enabled by the user when desired. The add-on would be responsible to extend the glTF exporter, as well as showing additional UI elements.
The add-on will need to be installed by Blender users by hand (with Godot notifying the user when this add-on is not found). This process will be simplified once Blender ships its built-in extension repository, working similar to Godot's AssetLib. When the .blend file importer runs, it will hint Blender to enable that specific add-on (if installed), to ensure that this metadata gets imported. Possibly show a warning if metadata is found in the .blend file, but the add-on is not installed.
Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams
Create a new git repository which is a Blender add-on.
The glTF exporter can be extended by exposing a
glTF2ExportUserExtension. GLTF import hooks can be added that can run code to add metadata. Eitherextrasorextensionscan be used to store this metadata in the glTF. Here's a short overview between the differences. IMO, an extension would make the most sense, if this becomes the official Blender integration path for Godot.Any features that are already standardized through other extensions, such as
OMI_physics_bodyetc., should be reused instead of redundantly recreating them in the Godot-specific glTF extension.The user interface can be extended by adding new properties to the corresponding properties pages (e.g. Object, Light, ... properties). For file-wide settings, a new panel can be added to the Scene or Output properties page. Where possible, re-use Blender's existing settings instead (such as eevee's shadow settings for lights).
Compatibility must be ensured, so that different combinations of Godot versions and add-on versions can properly import asset metadata.
Not sure how to handle unsupported object types, like Curves. I will create a prototype to see if the currently existing hooks are enough to make this possible, or if we need to implement such a hook in the glTF add-on.
I believe that if you opt into using the add-on, the Advanced Import dialog is no longer necessary for supported options. The ideal solution would be to grey out all settings in this dialog that are managed by the add-on, with a hint text informing the user to use Blender to modify these settings instead. Alternatively, we would need an option for Blender to load the
.importfiles to synchronize Godot changes back into Blender. This can probably not be done automatically, but is instead done via a button. Import hints like -col etc. should be ignored as well.If this enhancement will not be used often, can it be worked around with a few lines of script?
No.
Is there a reason why this should be core and not an add-on in the asset library?
Debatable, so please discuss!
IMO, by making this official, it greatly reduces the friction of the import pipeline for 3D assets. Making this official will guarantee support and compatibility with new features that both softwares have in common. The .blend file importer must also be modified if this were to be implemented as a Godot add-on.