How to write a python code for Add Feature Class To Terrain using interface?

Question

I am trying to write a code that creates a Terrain from lidar data (LAS). The problem is that the inputs are in Feature Dataset in GDB but I don't know how to write code so that using an interface. I won't write the whole code just the part that it's not working. Las data is saved in the new Feature Dataset created in the same script. I need to somehow replace D:\Google Drive\GDB2.gdb\data2\las with just las. I tried everything - by removing '' and it doesn't work. The error that I always get is: executing tool - Failed to execute (GDB). Can anyone help me? I wrote the parts of the code that are significant for creating terrain, the last line doesn't work:

import arcpy
GDB_Location = arcpy.GetParameterAsText(0)
GDB_name = arcpy.GetParameterAsText(1)
GDB_file = arcpy.CreateFileGDB_management(GDB_Location, GDB_name) 
out_dataset_path = GDB_file
out_dataset_name = arcpy.GetParameterAsText(2)
feature_dataset = arcpy.CreateFeatureDataset_management(out_dataset_path,out_dataset_name)

arcpy.DefineProjection_management(feature_dataset, "PROJCS['WGS_1984_World_Mercator',GEOGCS['GCS_WGS_1984',DATUM['D_WGS_1984',SPHEROID['WGS_1984',6378137.0,298.257223563]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]],PROJECTION['Mercator'],PARAMETER['False_Easting',0.0],PARAMETER['False_Northing',0.0],PARAMETER['Central_Meridian',0.0],PARAMETER['Standard_Parallel_1',0.0],UNIT['Meter',1.0]]")

....

l_g = 'las'
las_data = '{0}\{1}'.format(feature_dataset,l_g)
arcpy.LASToMultipoint_3d #in this step in created las

fd = feature_dataset
terrain = 'terrain'
terrain2 = '{0}\{1}'.format(feature_dataset,terrain)

    # Process: Create Terrain
arcpy.CreateTerrain_3d(fd,lidar_terrain, Average_Point_Spacing, "50000", "", "WINDOWSIZE", "ZMIN", "NONE", "1")

# Process: Add Terrain Pyramid Level
arcpy.AddTerrainPyramidLevel_3d(terrain2, "", "'1 5000'")

# Process: Add Feature Class to Terrain
arcpy.AddFeatureClassToTerrain_3d(terrain2, "'D:\Google Drive\GDB2.gdb\data2\las' Shape Mass_Points 1 0 1 true false las_ground_embed <None> false")

Answer 1

Try removing single quotes around the full path and use forward slashes. Like:

# Process: Add Feature Class to Terrain
arcpy.AddFeatureClassToTerrain_3d(terrain2, "D:/Google Drive/GDB2.gdb/data2/las Shape Mass_Points 1 0 1 true false las_ground_embed <None> false")

Example:

arcpy.CheckOutExtension("3D")
env.workspace = "C:/data"
params = "terrain.gdb/terrainFDS/points2 SHAPE masspoints 2 0 10 true false "\
   "points_embed <None> false"
arcpy.AddFeatureClassToTerrain_3d("test.gdb/featuredataset/terrain", params)