To add a custom 3D solid model certain rules must be met:

Support models:

Model must be defined in a separate .dwg file.
.dwg file should not have any other object in it (blocks, layers, entities), otherwise they will be imported as well.
Model should not be saved as a block. If a block is imported from a different file explode it.
Model should be placed on layer 0.
Units should be meters. If different units are used, they will be denoted as meters.
Support centerline should be placed in the absolute zero (@0,0,0)
If a foundation is modelled it should be placed in negative z-coordinates.
Support consoles should follow y-axis.
Support front side should follow x-axis.



                            

Tips&Tricks | Drawing insulator – How to create insulator strings for T&D lines



Insulator models:

Model must be defined in a separate .dwg file.
.dwg file should not have any other object in it (blocks, layers, entities), otherwise they will be imported as well.
Model should not be saved as a block. If a block is imported from a different file explode it.
Model should be placed on layer 0.
Units should be meters. If different units are used, they will be denoted as meters.
Insulator centerline should be placed in absolute zero (@0,0,0).
Symmetry line should follow x-axis.
Origin should be the point where the insulator would be attached to the support.
Insulator should be rotated so conductor direction follow z-axis.




Tips&Tricks | Drawing support – How to create utility poles for OHL