Are there any coverage simulation tools that handle 3D terrain modeling and multi-vendor network support?

Yes. There are several radio/network planning and coverage simulation tools that support 3D terrain modeling and can work in multi-vendor environments. A few well-known options:

• Forsk Atoll
  Strong for RF planning and coverage simulation across cellular, private LTE/5G, Wi‑Fi, and other wireless networks. Supports 3D terrain/building models and can import data from multiple vendors.

• Ranplan Wireless
  Known for indoor/outdoor 3D planning, especially for complex venues and heterogeneous networks. Supports multi-vendor planning and detailed 3D propagation models.

• P.I. Works / iBwave (for indoor)
  iBwave is widely used for indoor coverage design with building/3D modeling and multi-vendor device/system support. Good for DAS, Wi‑Fi, and private cellular in buildings.

• Ektec / Planet / similar propagation tools
  Depending on the vendor, some support 3D terrain, building clutter, and multi-technology planning. Multi-vendor support varies by data import/export capabilities.

• CelPlanner / TEOCO / Infovista Planet
  These enterprise planning suites often provide 3D terrain, clutter, and support for heterogeneous/multi-vendor networks.

What to look for in a tool:

• 3D terrain and building geometry
• Ray tracing / advanced propagation models
• Support for multiple radio technologies (LTE, 5G, Wi‑Fi, private networks)
• Multi-vendor config/import/export (equipment catalogs, GIS formats, network data)
• Integration with GIS data like DEM, LiDAR, shapefiles, and CAD/BIM

If you want, I can also give you:

1. a shortlist by use case (indoor, outdoor, 5G, Wi‑Fi, private LTE), or
2. a comparison table of the top tools with pros/cons.