I am guessing that the plants are "Face-Me" entities and consist of a single image. If after rendering them in ArchiCAD they are still grey, I would assume that it is due to ArchiCAD seeing the plants as textures rather than images and is not converting the image over into CineRender. If that is the case, you might be able to go into the related CineRender textures and add the image to the
Color Channel
. You might also need to do an alpha through a layer mask in order to not have them appear on a white box.
Rather than "Updating CineRender with Basic Settings" it maybe more worthwhile finding existing textures that looks similar to what you are wanting and using them to replace your SketchUp textures as there is a lot more depth to render engine textures than what is found in SketchUp.
Surfaces => [SketchUp Texture] => Delete => Delete And Replace With => [ArchiCAD Texture]
Ling.