duplicate materials

[loadpixels]

When converting a file I'm getting an input .dae with ~21 materials converted to ~169 materials. It appears that the converter creates a new identical material for every object it finds in the scene rather than just assigning an existing one to the object.

Obviously this has problems for further down the pipeline where reducing drawcalls by limiting materials is desirable.

[lasalvavida]

Hi @loadpixels. I would need to see the source model to say anything definitively, but the converter does not create a new identical material for every object in the scene.

I suspect what you are seeing is COLLADA instance materials with different overriden properties being split out as new materials in glTF, which is expected and unavoidable.

Feel free to attach your model if you'd like me to take a closer look.

[loadpixels]

Hi @lasalvavida - please find attached the original and the converted file. You can see multiple materials with the exact same properties, which I would have imagined would generally be best collapsed down to a single material. I don't believe that the geometry has any attributes that would affect the different materials, but perhaps I'm wrong.

Is this in anyway related to pull request #100 ?

test dae and gltf.zip

[lasalvavida]

Definitely something strange going on here. As far as I can tell, it looks like something may be tripping up OpenCOLLADA. There are some elements here that have the same id in the COLLADA, which isn't valid, they need to be unique within the document. For example, there are a bunch of nodes with the id "IfcWindow". Will look into this a bit closer later.

[loadpixels]

Thanks for looking at this, I've tried reexporting the DAE (using https://github.com/IfcOpenBot/IfcOpenShell) to enforce GUIDs on every element, but I still appear to get the same issue.

Test files attached

test ifc dae gltf.zip

[KermMartian]

I'm able to replicate this. I have a single COLLADA material set to two pieces of geometry, each of which has unique ids and names, and two identical GLTF materials are being created, each with the same name field. Let me know if there's anything I can provide to assist.

[lasalvavida]

Hi @KermMartian, if you could attach the model, that would be much appreciated. More data always helps.

[KermMartian]

Please find attached a sample model in DAE and GLB format. If I'm counting correctly:

DAE:

• 2 images
• 6 effects
• 6 materials
• 12 meshes
• 8 nodes in node library
• 125 instance_nodes or instance_geometrys

GLTF:

• 4 textures
• 12 materials
• 12 meshes
• 12 primitives
• 165 nodes

struct.dae.zip

[KermMartian]

bump Anything I can do to further assist with this?

[freeinform]

Same problem, materials are duplicated,
as well as something with numbers:
COLLADA:
<effect id="Стекло-fx"> <profile_COMMON> <technique sid="common"> <lambert> <diffuse> <color>0 0.5019608 0.7529412 1</color> </diffuse> <specular> <color>0.5 0.5 0.5 1</color> </specular> <shininess> <float>12</float> </shininess> <transparency> <float>0.1</float> </transparency> </lambert> </technique> </profile_COMMON> </effect>
GLTF:
{ "pbrMetallicRoughness": { "baseColorFactor": [ 0.0, 0.501960813999176, 0.7529411911964417, 1.0000005993542468e-22 ], "metallicFactor": 0.0 }, "alphaMode": "BLEND", "name": "Стекло-fx" }

[KermMartian]

bumpity bump Anything I can do to help with this? It's a serious problem for us.

[lasalvavida]

Fixed in #266