I downloaded the DAE file from Nasa Mars Rover, and it looks great in the Mac Preview.app.  But when I bring import it into Prefab3D, it looks invisible.  Is this because the materials are not coming in properly?

I don’t know what is wrong with this collada. I saw materials were not set as expected but I saw that all meshes were not having correct transforms. I’ve reexported the collada and it loads then ok. Which makes no sens for a format that is supposed to be an exchange format…
In case you want it, you can download as project here: http://www.closier.nl/downloads/rover.zip

Wow, that was quick!  I downloaded your file and it looks great.

What did you use to reexport the collada?  I don’t see that option in Prefab3D.

Thank you very much!

AC3D has a very extended dae parser, probably one of the best Collada parser I know for static scenegraphs. Reexported it from there.
Obviously its exporter is working well too and following specs 1.4.1 that Away parser does support. Prefab has no Collada export option.

Cool… thank you!