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I'm trying to get a model taken from 3D scan using the Autodesk 123D Catch app into Aurasma. According to their FAQ, this needs to be exported via OpenCOLLADA and that's why I've installed Blender for the first time. I've downloaded my model as an .stl and also a .obj and have managed to open it up in Blender and that's as far as I've got.

According to the Aurasma instructions I need to, "Upload the following files to Aurasma Studio as a .TAR file (Windows use 7zip and on Mac use GUItar). • DAE file created in 3D using Collada exporter • PNG’s for textures • PNG thumbnail named ‘thumbnail’ with .PNG extension

I have managed to export the model as a DAE file but it ends up being over 100mb because of the complexity of the mesh (I'm guessing). I've tried using Decimate to reduce the model complexity but this seems to cause issues with the textures no longer matching the model's topography.

I have no idea what I'm doing here or how to go about getting the texture PNGs etc, so if someone could talk me through step by step I'd be really grateful. Bear in mind I've never used Blender or anything comparable!

Many thanks

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Decimate modifier doesn't take in account UV maps.

With the collapse option enabled it:

...merge (s) vertices together progressively, taking the shape of the mesh into account

While mergin vertex, it likely happens that the UV mess up. You should create a new UV map for the decimated object and stick the original texture to it.

  • Start from duplicate (Shift+D) your mesh. Rename the source object "Highpoly" and the duplicated one "Lowpoly" (keep them in place, overlayed)

  • Add and apply a Decimate modifier with the wanted settings on the Lowpoly object

  • The UVmap of the Lowpoly has now been destroyed in the decimation, you must re-unwrap your model.

  • Bake the original texture from the Highpoly to the Lowpoly as shown for example in this video (the only difference is that you should bake "textures" instead of "normals")
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    $\begingroup$ You need to add more details on how to bake the texture, otherwise the OP, probably, won't be able to do it. $\endgroup$ – someonewithpc Oct 15 '15 at 15:07
  • $\begingroup$ Thank you so much for this. I'll give it a go but it does sound quite convoluted for someone not yet familiar with all the Blender jargon. A quick explanation of how to "bake the original texture" would be much appreciated. $\endgroup$ – Ludocity Nov 1 '15 at 10:11
  • $\begingroup$ You are both completely right. I didn't fully developed the answer intentionally because I thought it would come out pointlessly long. I would like to give advice about the path to follow rather than a step by step instructions. Even "re-Unwrap" its not an easy task, so it would also need a proper explanation @someonewithpc, and maybe, for a beginner, other steps too. I think it would not be a good idea to answer here all the question that may come up: there are lot of resources outside that cand do it better. I'll link them asap. $\endgroup$ – Carlo Nov 1 '15 at 10:59
  • $\begingroup$ Let me know what you think, because I plan to write down a tutorial about the topic anyway (sooner or later) but I thought this was not its place to be. $\endgroup$ – Carlo Nov 1 '15 at 11:07
  • $\begingroup$ @Carlo I guess you do have a point $\endgroup$ – someonewithpc Nov 1 '15 at 12:10

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