1. Here's how:
1.1: In your 3D/CAD software, start by assigning a random roof texture to the roof. Then place the texture, so that the roof texture is facing the right way on all faces of the roof:
1.2: After importing the model in Lumion and assigning a roof material to it, you will notice that the roof tiles aren't facing the right way.
What you are seeing is the automatic Box-mapping Texture Placement in Lumion. This texture placement mode does not take slope angles or Imported Texture Placement, into account.
Box-mapping is used when the Map Scale slider is set to a value that is higher than 0.
1.3: Set the Map Scale slider to 0 to switch to Imported Texture Placement mode.
The roof tiles are now using the texture placement from SketchUp.
This ensures that the roof tile directions match the ones in SketchUp.
However, the scale of the Lumion material is now too small because the source texture in the 3D/CAD software covers a smaller roof area than the texture in the Lumion material:
1.4: To make the roof tile material bigger in Lumion, you will have to increase the size of the texture in the roof material in your 3D/CAD software.
In this example, we set it to 4.2 x 2.7 meters and save the .SKP (SketchUp) file again.
1.5: After re-importing the .SKP (SketchUp) model in Lumion, the roof tiles now have the right size and the right orientation:
1.6: If you don't want to change the size of the roof tile texture in your 3D/CAD software, you could consider assigning different materials (with unique names in your 3D/CAD software) to the parts of the roof that need to be aligned differently. Then re-import the model in Lumion, and use more than 1 Lumion roof material to align the material as desired.