I have building models (with no textures) in Sketchup (15 and 17, free and Pro) that I close into solids and export to Collada. However they appear to sometimes break and sometimes wont reimport into sketchup. Blender however will open the files and re-export them to dae again. The new dae files are typically larger but can be opened in sketchup and other applications. Both have triangulated faces. This tells me that Blender has a better collada import and export tool. Well done. Can anybody tell me the technicalities of why it is better? The sketchup community seems quite quiet on the matter. If there are any converts online who are at that level...
I don't know Sketchup for it's not open-source neither do I use it much but let me explain Blender's collada exporter.
First why is Collada so unique other than it being libre(open),
COLLADA is designed to be highly flexible. It can store application-specific data using its mechanism at various places in the document. You can insert this data in your DCC tool using the user properties mechanism; the COLLADA import/export will then carry this information for you, so there is no need to change the exporter source code to carry your application/game-specific data into the COLLADA format.
This means that sketchup's implementation of it has flaws of implementation for it's a relatively simple to use format, and it just records data and passes it on. So the data recorded might be written improperly by the software.
Blender currently uses the opencollada library to provide support for collada import and export. And as it's open, it's more mature than the rest of the libraries used by other tools that the power of being open.
I believe but there are repos like https://github.com/godotengine/collada-exporter. That improve the implementation for game engine Godot.
That's probably all there is to the implementation.