create 3d objects and separate roof and body

Hi @totree30​,

Assuming that footprints are 2D, DEM is ground level, LAS include roof tops:

• Assign unique id to footprint with Counter
• Drape copy of footprint by LAS data - this will be the eave line
• Drape another copy of footprint on DEM - this will be floor line
• Extract lower bound of floor line with BoundsExtractor
• FeatureMerger to merge floor line bound attribute on eave line
• Extract upper bound of eave line, then subtract lower bound of floor line to get wall height
• Extruder to extrude eave line by negative wall height to create walls
• Clip LAS by copy of eave line with Clipper
• Use clipped LAS and copy of eave line in TINGenerator to create roof surfaces - group by footprint id

This should give you wall surfaces and roof surfaces for each building, linked by footprint id.

Oh and floor line as well! I used the Lowest point of LAS and assign it as a floor elevation.