Add Generate LODs, Shadow Mesh and Lightmap UV2 options to OBJ mesh import #94108
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This option was enabled by default, but it did nothing regardless of whether it was enabled or not.
Calinou
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…mport This puts OBJ mesh import on parity with 3D scene import. It's now possible to have the same level of optimization as imported 3D scenes while using the OBJ mesh workflow.
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| if (p_generate_lods) { | ||
| // Use normal merge/split angles that match the defaults used for 3D scene importing. | ||
| mesh->generate_lods(60.0f, 25.0f, {}); | ||
| } | ||
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| if (p_generate_shadow_mesh) { | ||
| mesh->create_shadow_mesh(); | ||
| } |
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Note: if you perform these steps before lightmap UV2 generation, the resulting mesh will be broken. It'll display with the wrong transform and no material (pure black color). I have no idea why this happens, but I figure I'd mention it either way. Putting up a MRP for this will likely require exposing additional ImporterMesh methods (such as create_shadow_mesh() and lightmap_unwrap_cached()).
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Nice work. I would look to see an option to not to try to import .mtl files when importing an obj. It is a constant annoyance to see errors in the console that it can't find the corresponding .mat file for an obj. Personally, I never use the .mtl file, so only export it to stop Godot spitting out the error. Godot will see face groups fine with just the .obj itself. |
@fracteed To be clear, you're talking about .mtl files referenced by a My opinion is that it is data which is directly referenced by the obj file, so it would be wrong not to try to load it. I don't think we should add an option to disable an error, especially when there are cases where the error is helpful. If you really don't have the .mtl, it's also relatively easy to edit the .obj file and remove the |
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@lyuma yeah, I meant to write mtl. There should at least be an option to turn off the requirement for it for those that just need the mesh information. If I have hundreds of objs in a project, it is not viable to fiddle with editing obj files. Just went and checked on a current build to see if anything had changed, as I probably wasn't very clear with my initial comment. Yes, you can export objs without an mtl and they import fine without any error messages. But the issue is that you can't get material group selections unless you have the mtl file exported from Blender. It is a stupid quirk in the format, since if I export an obj from blender with the mtl and then delete the mtl, Godot will still import it with the material groups intact, it will however give an error message. One of the main reasons I delete the mtl is that Godot deals with them badly in general. For one, they do not show up in the file system, and secondly, when you move an obj from one folder to another, it does not move the mtl file along with the obj. So after having hundreds of files added and deleted over the course of years in a large project you end up with a ton of errors looking for mtl files that are actually not needed, and are either in other folders or long deleted. I guess the ideal would be if Godot could actually just read the material group info directly from the obj, since the face info is in there, as you can can export an obj with material groups and no mtl. |
#94102 fixes the spurious error message if you have no MTL file referenced in the OBJ. However, I think a missing MTL file should print a message if the OBJ is trying to reference it, as it can be the source of a legitimate error.
sd should be able to automate this easily. Something like this can be used to comment out all material file definitions in OBJ files in the current folder (recursively): # Use this to make `**` work on Bash (not required on zsh).
shopt -s globstar nullglob
sd "mtllib" "#mtllib" **/*.obj |
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I think we should add an import option for OBJ to ignore MTL files (i.e. just skip |
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I think the extra processing steps should be done in import_scene or at the end of parse obj, not inside the loop? An .obj file with multiple materials or surface groups will add multiple surfaces to the same mesh, but with this change shadow mesh or LOD or lightmap generation will be called on the entire mesh for every newly added surface. For lightmaps this might be mitigated with a cache, but for LOD/shadow meshes it looks like the code will redundantly reprocess all earlier computed surfaces. |
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Also after #94241 it would make sense to call |
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Since #94241 has been merged. Could you add |
(can be merged independently).
This puts OBJ mesh import on parity with 3D scene import. It's now possible to have the same level of optimization as imported 3D scenes while using the OBJ mesh workflow.
LOD and shadow mesh generation are enabled by default, so that users can benefit from the same performance regardless of how they're importing 3D objects into Godot. Lightmap UV2 generation is disabled by default to mimic the 3D scene import default (and PrimitiveMesh).
Testing project: test_obj_import_lod_shadow_mesh_lightmap_uv2.zip
Preview
OBJ mesh import options
Lightmapped OBJ mesh having its LOD level changed
obj_lod_lightmap.mp4
LOD disabled
LOD enabled (Mesh LOD Threshold = 1024)
This shows the most decimated LODs for comparison purposes.
TODO