March 25, 2016, 12:37:43 am
Hi vicmaria
Good to know that's working for you.

An invisible face should only occur for backfaces with SketchUp Default Material. In such cases it can be resolved by flipping (reverse) the surfaces to correct the visible face so that it's outward facing. That might happen for example if the backface was used to extrude and push to create a front face.
The paint backface material option DerekW mentions is another solution. This does however add to the surfaces that need rendering by Lumion so has a little bit of an impact.
There used to be an issue a few years back regarding Default Materials, but that has been sorted, so we would need the details as per Morten's post from vicmaria in case there is some other cause.
Derek: if you are getting that for outward facing surfaces, please send us the file and details so we can investigate further. Thanks.