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I guess the question/issue is related to DCC tool[s] not about COLLADA (or SceneKit) itself (directly)

FWIW, COLLADA exporters do not have to keep previous IDs or SIDs. All element IDs, SIDs,...

I have some plans for this in the future :)

The best thing to do is optimize meshes in COLLADA files, also whole scene can be optimized, unused elements could be removed... There are some mesh optimizer libraries but I'm not sure they can work...

Addition:

AFAIK, FBX SDK can load COLLADA files, maybe it can also work on Android I don't know. If Autodesk's proprietary license is not an issue for you, you could try it.

You are free to try it :)



There are some old libraries like FCOLLADA but most of them are abandoned. @Mick P. is working on COLLADA-DOM, you can ask status of project to him.

I'm also...

FWIW, I get email notifications for new forum threads or updates, but I do not get email notifications for Inbox/Messages (don't know how to fix it) :S

I guess you have MVP matrix in shader and you need these matrices

1. [M] Model transform comes from node element
2. [V] Camera transform comes from node element. View matrix is inverse of this....

Do not worry, if your questions are related to COLLADA spec, you can ask simple or complex questions.

COLLADA uses multi-index buffer to store primitive indices. It means that you can use...

Because COLLADA uses multi-index buffer. In this may arrays may have different lengths.



What do you mean?

Cesium has great community, you may want to move this issue to there: https://github.com/AnalyticalGraphicsInc/cesium by creating new issue: https://github.com/AnalyticalGraphicsInc/cesium/issues/new

It doesn't matter what data you put in COLLADA file as semantic or as extra/extension. Importer and/or renderer must parse and understand that data, otherwise it will no affect. It is not issue...

Here an example of two-sided rendering: https://en.wikibooks.org/wiki/GLSL_Programming/GLUT/Two-Sided_Surfaces

If you have normal like vNormal in fragment shader, then you could use -vNormal as...

I can't say I understand what are you trying to do, so I'll give a try;

I think this is related to other question. Again COLLADA defines face attribute for cube mapping. Maybe this is what you are...

Are you trying to render double-sided surface, if not what do you mean with side? AFAIK, COLLADA and most other formats only specifies an image and texcoords for texture, not side. If you want to...

After followed a few tutorials about sport light implementation, you can do what you want here. All light properties already defined in the spec.

The current version of COLLADA does not support PBR materials. In the future maybe, with extensions maybe. Probably you can get that value in COLLADA file with Blender extension if they write it to...

Hope you are not a spam bot, I'm not sure :)

Yes default light direction is as what you described (0,0,-1).


Actually you already answered your question here. You must apply light transform...

It would be great to collect some bugs and list them in some place (pinned post or/and a wiki page). We and/or some others may fix some critical bugs by reading this post or wiki page.

By the way...

yeah this is what I was talking about. Opaque object's transparency was exported as 0 which had to be 1. I fixed that for old versions of SketchUp while importing.



Maybe I should contact...

Recently I have implemented transparency (all modes I think) in my render engine. It seems some tools exported transparency parameter wrong in past. They may have fixed that bug now, but there are...

+1

Plus; if you develop a tool to export it, then I suggest that test it with IDENTITY transforms first, maybe there is something wrong with transforms which causes different look

What do you mean with "if the normals where inverted", if you invert normal then you change also ligting so only inside of mesh will get lights (if there is a light source). Probably this is why you...

https://www.khronos.org/files/collada_spec_1_5.pdf
https://www.khronos.org/files/collada_spec_1_4.pdf

Check "Texturing" section in Chapter 7, it explains how to use texturing in COLLADA.

Giorgio, there is also glTF format for runtime (http://github.com/khronosGroup/gltf),

AFAIK, Cesium.js uses glTF to render 3D tiles (glTF + CityGML or more sources):...

@remi, I'm so glad to see you here,

@giorgio.denunzio, if you have Blender then you can export a simple CUBE or other scene as COLLADA, COLLADA is default exporter of Blender.

Most modeling...