Small sized mesh from Revit. Long lightmap time with bad results

Questions & Answers
1

So, originally the file is a .IFC file I got from an architecture company. I imported it into Revit, exported the 3d Model as FBX and put it into Unity.
Note : I have little experience with Revit.

Once, the FBX is in Unity,I had extremely bad results with Lightmapping with everything in the model turning black after the baking was done. This is with the “Generate Lightmap UV to UV2” option selected in the mesh model.

I have many other objects in the scene including some furniture and some simple objects like cubes and spheres all of which seems to be baking fine in minimal time. And yet, this mesh is still weirdly baked. To reduce the baking time, I edited the mesh in Revit, removing 95% of it to simply have a plain like surface and then imported it into Unity to lightmap and it still takes an 15 minutes to bake a 350 KiloByte FBX Mesh resulting in the same ugly black object.

Any help would be appreciated on why this is happening. Have been trying to fix this for hours with no good results.

TLDR :

  1. 540 KB FBX Mesh takes 10 minutes to bake while I’ve seen faster results from much bigger files .
  2. Baking it results in a blackened object while other objects in the scene look great.
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Thanks

2

You can try to convert the IFC file using IfcConvert (from the open source IfcOpenShell Library) and turn the IFC into Collada or Wavefront format, to load inside Unity.

Some examples are on my blog http://cad-3d.blogspot.com