SketchUp Twilight Renderer:Group's Default Material

If you look closely at the render in my last post you will notice something wrong with the fuel cells at the rear of the craft - admittedly you'd have to be really anal to notice but that's my job. The fuel cells are supposed to have a red background color with a white frame work and that is how they display natively in SketchUp:

Objects as SketchUp displays them

However, in the Twilight render they displayed almost completely white like this:

Twilight render with issue: background of hexagon should be red

The helpful people at the SketchUp Twilight forum suggested that this was because I had reversed faces in my  component. The problem is that Twilight interprets the material at the front and therefore to be rendered very slightly differently than SketchUp itself.

It turns out it was slightly more complicated than that. To model as efficient as possible I have nested components:

-> Group of 7 components

|--> 1 Fuel Cell Component

  |--> Hexagon Component 

The reversed face was in the hexagon component which was painted red. The group of 7 components had a default color of white. Once I found a removed the default color from the larger group the hexagons started to paint correctly.

Correctly painted render

Of course, if I'd paid attention to reversed faces in the first place this wouldn't have been an issue. Also, if I hadn't accidentally given the group a default white color this wouldn't have happened either. This isn't a biggie but it took a while to find out what was going on but it is a lesson learned: keep your reversed faces in order to avoid problems or inconsistencies with materials later.