1. Here's why
Unlike the section plane/box function available in Revit and ArchiCAD, the Clip Plane in Lumion does not 'know' whether an object is solid or not, so walls and other solid objects will appear hollow.
Example of hollow walls and floors when using the Clip Plane in Lumion:
2.1: In Lumion 12 and newer versions only:
You can use the Clip Outline option to render outlines along the edge of the visible geometry that is clipped. It is possible to set the width and color of the outline as well as which Layer to clip. Geometry that is facing away from the camera, and therefore isn’t visible won’t have a visible outline.
2.2: In all versions of Lumion:
2.2.1: We recommend using the section plane/box functionality in your 3d modeling software if that feature is available and it caps clipped objects as solid surfaces.
Example of capped walls and floors when using the Section Box tool in Revit:
Section Planes in SketchUp cannot be exported to Lumion so you will have to use a plug-in:
- External Link: Eneroth Slicer
2.2.2: Consider using the Variations function, and the Variation Control Effect to show the clipped version of the model along with the original version: